In this posting, I am going to look at all the cards that cost Phyrexian mana (PX is one Phyrexian mana of the colour specified by the standard WUBRG notation); the ones you can either pay the one coloured mana for, or two life, and some of the artifacts that have an ability that uses this mana. In Mark Rosewaters column on the subject, he said "I'll write an article soon about the impact of Phyrexian mana on the color pie—it's too big an issue to discuss today", which is a pretty big understatement, as the spilling of effects is very severe in some cases (but hey, at least there's no 'destroy enchantment' that red or black can get to play). I will be looking at limited (drafting mainly), constructed (standard, I follow it a bit and use some sort of rogue deck when I do play occasionally) and casual (fairly general, probably thinking about multi-player as it's what I usually play if I'm not playing the above two formats).
I'm going to attempt to give a score out of 5 for the different formats I have defined, but will probably ramble on a bit about each one (as I have been doing so far). Anyway, lets start.
Apostle’s Blessing 1PW
Target artifact or creature you control gains protection from artifacts or from the color of your choice until end of turn
Seems OK in the current set, somewhat underwhelming though. It's better than the green instant in Scars that give pro-artifact in the sense that you get to choose a colour if you want, but worse in the sense that you don't get to draw a card. Might be something to think about side-boarding in against a draft opponent who has a lot of spot removal and you have limited decent threats. Similarly, it could be something worth playing in a casual group if you often face a lot of removal, although I'm sure there are better protection spells in white, so it would only be worth considering in a non-white casual deck.
Cathedral Membrane 1PW
Creature Artifact – Wall
When Cathedral Membrane is put into a graveyard from the battlefield during combat, it deals 6 damage to each creature it blocked this combat.
On the surface, this one seems quite good. It can be played turn one in any deck so long as you don't mind paying the two life, but is a fairly defensive card that seems to be targeted at slower decks. I would say it is worth playing in most decks, particularly slower ones because even if you pay the life there is a good chance it will break even or get ahead on life, just through preventing damage (or even preventing potential attacks).
There are a few 0/4 walls that get played in standard now, and while this is more likely to get killed in combat, it also means it is more likely to take an opponents creature with it. The main downside is that it is easier to get rid of with lightning bolt (a red deck would be the best deck to play against with this, which is almost certain to be running 4 bolts).
So in limited, I would probably play this is most decks unless I was playing a very fast deck. In standard, this would fit into a control deck, or potentially a combo deck needing to keep some creatures at bay. For casual, this would be at home in most Johnny-style combo decks if they need to buy a few turns, and fairly decent in many decks that get played a lot in multi-player.
Marrow Shards PW
Marrow Shards deals 1 damage to each attacking creature.
This is a worse version than the one that puts a -1/-1 counter on each attacking creature from the last set, in terms of power level (but can be played in non-white decks so that's a plus). That said, its still a fairly decent trick and would fit into most white draft decks, and might be worth considering putting it into a non-white draft deck, although you would have to bear in mind that you only really want to pay the two life if you're going to get rid of two or more 1/1 creatures (two breaks even on life, and has the bonus of removing two creatures), or if they're attacking with something bigger with one toughness. I guess it might be OK even if it only kills the one creature for two life if that creature either has a high power or is very hard to remove and you will have trouble doing so another way. I think this will be more likely to come in from a sideboard than being in the main deck like the -1/-1 version from the last set.
In standard, there are generally better options available, and in casual, it might be a fun trick, but would be more of a meta-choice (if you play a lot of 1/1 swam decks)
Norn’s Annex 3PWPW
Creatures can’t attack you or a Planeswalker you control unless their controller pays PW for each of those attacking creatures.
This will can be easily put into casual decks, and could potentially show up in some standard decks, for similar reasons to the wall I looked at earlier. In a non-white deck, the main thing to weigh up is whether you will stop more than 4 damage from attacks while it is in play to make it worthwhile. Playing against it, the thing to think about is whether it will be worth attacking with something. The general rule of thumb will be that you might break even with a creature with two power (or one if it is infect), but the opponent can still potentially block it. Its not the kind of thing you attack into if you are behind unless you have a good reason, and you really need to be breaking even on the life swing if you and your opponent are about equal. If you are ahead, it makes it more tempting to attack into regardless, to keep the pressure on, but not as much as you might otherwise as you could lessen the gap unintentionally. Something to remember when facing this is that it is an artifact (I think most other times an effect similar to this has appeared was on an enchantment).
If there is anything in this set that will make people look at alternate win conditions (infect to some extent, that but also involves attacking, I'm mainly thinking about milling), this will be it. Either that or it will make blightsteel colossus appear more often ;)
And if it gets played a lot, I wonder if people will just start 'splashing' some plains to reduce the life loss. If the rest of the deck has decent fixing, it shouldn't be too hard, or could just involve swapping a few basic lands with dual colour lands.
Porcelain Legionnaire 2PW
Artifact Creature – Soldier
This is very aggressively costed. If you don't mind the two life it comes down turn two and able to block most things that could also be played that early in the game, and unless they also play something with first strike, it will stay around to block some more. If you're not in a need to be defensive early, for the two life on turn two, this is an upgrade on the 3/1 vanilla creature from Future Slight. You're going to want to play this in most non-infect limited decks (maybe even some infect decks if you do need a good early defender) as it can start applying pressure early on.
The first strike makes it good for casual multi-player as it can dis-encourage opponents from attacking you early on and turning their attention elsewhere. I think it has some potential in standard, for slower decks it can put up a good defence against decks with lots of small creatures (swarm) which may make the two life worth it, and for faster decks it is an aggressive threat that came be played early with no coloured mana required.
Gitaxian Probe PU
Look at target player’s hand.
Draw a card.
This is an interesting card, and one that I particularly like, although that might be because it fits into a casual deck I have. I can see it seeing play in limited as in a non-blue deck you are effectively cycling for 2 life, which is better in a smaller limited deck than a larger constructed one as it brings you closer to the smaller selected of bombs and removal you have.
In constructed, it looks like a bad version of Preordain in some aspects, but as that is apparently played as much as Jace the Mindsculptor, I wouldn't be surprised if this starts seeing a lot of play, particularly in non-blue decks that can't play Preordain. Yes, there is no card filtering/selection, and all it does is replace itself, but looking at a players hand can have some marginal benefits (i.e. you know if they have a counter/removal spell so you can plan your turn based on that information). The best thing about this card is that it is 'free'; and free card draw is very powerful. I can see this being a useful tool in a mono-black discard based deck; there are three good turn one black discard spells now (including the one in this set), but they all target different things; CMC under 3, non-creature non-land, and creatures and Planeswalkers, so a turn one swamp, followed by Gitaxian Probe will tell you which of your three turn one discard spells to play, and even give hints as to what ones you should play on the next turn. It other decks, it thins the deck by four cards (people play the sac lands in mono-coloured decks), which can be an important thing to do if you require greater consistency than you get with 60 cards.
In casual, I'm sure this will be played in many a random combo deck. Its free card draw and ups a storm count if in a storm deck, and the looking at an opponents hand will let you know if an opponent has any cards in their hand that could disrupt your combo.
As a slight aside, here is the core of a casual deck I've put together that will greatly like this card (and the Phyrexian-green pump spell):
Wee Dragonaughts, Brute Force, Psychotic Fury, Distortion Strike, Double Cleave (I have also been looking at Kiln Fiend, but that was previously the creature from Future Sight with Wizardcycling). I did have Shadow Rift for a while, but it was mostly replaced with Distortion Strike. Mutagenic Growth will fit in nicely here.
Ponder, Preordain, now Gitaxian Probe. I have also had Brainstorm and Serum Visions in here (but the latter is the worse version of Preordain). Mystical Tutor is also handy for this.
Lotus Petal, Rite of Flame, Manamorphose, Simian Spirit Guide
Various red/blue dual lands
The idea here is to land a Wee Dragonaughts, and attack with at least 10 power and double strike. With the fast mana, it is possible (although you have to be lucky) to get the creature out on turn one, then Rite of Flame to play Psychotic Fury and Brute Force to attack for exactly 20 on turn two. Like I said, you have to be very lucky. The deck is fairly fun, it doesn't do too much and can occasionally win out of nowhere, but is pretty easy to disrupt.
Mental Misstep PU
Counter target spell with converted mana cost 1.
There has already been many discussions online about how crazy this will be in legacy, countering things like Æther Vial, Goblin Lackey, Top, Brainstorm etc.
Including this spell, there are 7 one mana Phyrexian (i.e. 'free') spells, not counting the one mana and X spells. There are also some other good one mana spells that could be worth countering.
In Limited, this can stop a Galvanic Blast aimed at one of your creatures, or counter a Kuldotha Rebirth (after they've already sacrificed an artifact as a cost). It can prevent the metalcraft pump spell, and the new white spell that either taps or exiles a creature. It might be worth playing, but probably not all the time, a fair portion of what is can counter is going to be a removal spell of some kind, so defiantly something to consider countering, but I would say that more often than not this should start in the sideboard and come in if you see a lot of low costing spells that you want to counter. Obviously, if you often see one mana spells in Limited, then it would make sense to maindeck, although initially it would be more of a meta-choice (and may be a good way to go if one mana spells generally become popular in Limited).
In standard, this can counter a lot more, most of what will be played in red decks (Lightning Bolt, Goblin Guide), as well as the ever popular Preordain, the increasing number of one mana discard spells, and even itself, as I'm sure it will be seen a lot in constructed. Paying life isn't always going to be on the top of your list when playing a red deck, you are up one life against a lightning bolt, but that's not too bad if you're saving a creature they may have to use another spell on to get rid of. Unless your deck can get a good defence early on, it would be worth countering a Goblin Guide, it evens out on the first turn, but so doesn't pressure you to get something to block or remove it the next turn, so can save you a couple of life if your deck isn't that fast.
I'm not sure about this in casual, it is generally going to depend on the group. Most casual groups I have played with don't often run counter spells at all, so this spell might be equally ignored. I suspect the most it will see play in casual decks is if your play group often plays combo decks that you have trouble disrupting (but at the same time, it has to be a combo deck that relies on a one mana spell). This might make it possible to play a more controlling deck in multi-player, as you will have the ability to stop two spells on the first round of turns; it will give you a bit more reach in the start of the game to allow you to set up into a more controlling position.
Phyrexian Metamorph 3PU
Artifact Creature – Shapeshifter
You may have Phyrexian Metamorph enter the battlefield as a copy of any creature or artifact on the battlefield, except it’s an artifact in addition to its other types.
In Limited, this allows a player of any colour deck to copy the best current creature or artifact, which for 3 colourless and two life, isn't that bad really. Keeping itself an artifact is nice too as it helps with metalcraft. There's not really a reason to not play this.
In Standard, there are a lot more silly targets for it; the titans for one. I can see this being a boon for fast decks that have a low curve; if they're not planning on easily getting up to higher levels of mana, and don't manage to win by the late game, they can catch up without having big creatures in the deck by just copying their opponents best threat.
This looks fun in casual as well, as there is a larger chance of playing with and against big fun creatures and artifacts, ready to be duplicated.
Spined Thopter 2PU
Artifact Creature – Thopter
I think this is more of a limited card then anything. The stats aren't great for the cost, even on turn two; there is the white pegasus that you don't have to pay life for. Its a cheap flyer so is very good in most limited decks.
I doubt it will see much played in standard, and maybe in casual for some decks that want some early and fast evasive creatures. Possibly if someone wanted to make a thopter tribal deck (that sounds kinda awesome actually, but that's just me).
Tezzeret’s Gambit 3PU
Draw two cards, then proliferate.
This allows any colour to draw two cards (and card drawing is always good). The proliferate may occasionally be of some benefit, but this is mostly about the card draw. In limited, it draws you further into your deck, and the current limited (obviously) has a large number of counters you might want to proliferate. In Standard, its going to allow some non-blue decks to have some card draw, but will see a bit more play in casual, to give decks more chances to draw into more fun cards.
The things to bear in mind here, is that as it is drawing two it is replacing itself and then drawing a card, leaving you up one card, which isn't too bad. It can be seen as a colourless "Sign in Blood" (that can't target your opponent). The proliferate may occasionally be relevant, but not always.
This will be useful in decks that want to play a lot of Phyrexian mana costing cards, it fits the theme but most importantly allows you to draw more cards, and if you are playing cheaper spells you are going to run out of cards quickly and will need to draw some more. Getting back life however...
Target creature gets -5/-5 until end of turn.
This is a very good card, removal is always premium in limited, and this is great, with the bonus of being played in any deck. This reminds me a little bit like Vendetta from Rise of the Eldrazi, which was first pick quality. With that you lost life, and with this, while it doesn't destroy, and only shrinks something, that is better against creatures that are indestructible, and if you are playing black anyway, may not even cost you too much life.
I'm not too sure about how much play this will see in Standard, it doesn't get the titans, but gets most other things (Baneslayer Angel for example).
It will be a lot more fun in casual, particularly multi-player as it can allow a player to keep one mana of any colour up and be able to kill off an attacker.
The thing to bear in mind with this is that you want to use it as early as you can if you're not going to be able to pay the coloured mana for it. It can get rid of a 5/5 so the 4 life will mean you are up one life in total (anything smaller and you either break even or loose out initially), but will stop you from taking additional damage on later turns. This is something you really want to use on utility creatures more than anything, particularly if you don't have many other ways to remove them.
Pith Driller 4PB
Artifact Creature – Horror
When Pith Driller enters the battlefield, put a -1/-1 counter on target creature.
This will be alright in some limited decks; it can kill off some smaller creatures on turn four if you're not playing black, but it might not be as worth it by then. The value goes up if you're playing an deck with some proliferate cards as that is somewhat relevant here.
In standard, its not going to be that great, and in casual it might be fun in some decks that abuse enter the battlefield effects (but there are better cards for this, mostly black, but this can go into non-black decks if required).
The main bonus this has is that is is harder to remove than some other creatures. Bolt needs something else to do one more damage, and can't be targeted by Go for the Throat or Doom Blade (but is open to artifact destruction, so that's something to bear in mind as that's fairly common).
Postmortem Lunge XPB
Return target creature card with converted mana cost X from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step.
This seems like a fun card, surprise reanimation! :D
You are almost certainly going to be able to play the X cost as you would have had to play the mana cost of the creature in the first place.
In limited, it allows for the reuse of one of your threats which will usually be in, well, limited amounts.
I'm not too sure about standard, I can see it in some infect decks for an extra push or to help swarm an opponent if they're close to 10 poison counters.
It looks like a fun casual card, you can bash in with big green creatures again without having to play black! :D
Surgical Extraction PB
Choose target card in a graveyard other than a basic land card. Search its owner’s graveyard, hand, and library for any number of cards with the same name as that card and exile them. Then that player shuffles his or her library.
This isn't going to be playable in limited, apart from a few rare occasions. Most decks are lucky to get more than on particular spell, and if they get multiple, then to play this they would have had to play the card first, and then you might only remove one more, and if they have multiple copies of the same cards, they would have had to have been passed them a few times, so are unlikely to be amazing if they've not been picked by numerous other players. If anything, the best use for it in limited would be to look through your opponents hand and deck to see what cards you need to look out for and play around.
In standard, the best application for this would be to get rid of a card you really, really don't want to deal with. Even then, it might be good in a mono-black discard based deck (there are 3 different turn one discard spells in standard, playing this following a discard spells can seriously mess up an opponents game plan).
In casual, this gives the effect to non-black decks, but I don't know how often it will be played, as it is more of an semi-answer than anything else. Some friends of mine have called it really harsh, so I think it will be popular in some groups. This card will have 'griefers' everywhere interests piqued.
Vault Skirge 1PB
Artifact Creature – Imp
I quite like this card, its an early evasion-lifelink creature, which is good if you are playing lots of Phyrexian mana symbol cards as you can lessen the effect of paying as much life by gaining some back.
In limited, its an early evasion creature, somewhat hard to remove (black artifact) and can be played in most decks. I wouldn't say its first pickable apart from really bad packs, but I would happily take it fairly highly (but not over bombs or good removal).
It might go into some standard decks, ones that play equipment can take advantage of the lifelink, other decks can play it as something that can block a Squadron Hawk.
Casual might like it more, its a cheap creature with some simple but fun abilities, what's not to like?
Act of Aggression 3PRPR
Gain control of target creature an opponent controls until end of turn. Untap that creature. It gains haste until end of turn.
Colourless threaten on an instant? Wow...
This is something that you really need to bear in mind when attacking an opponent with three lands untapped. It can lead to some serious blowouts in combat; steal their biggest creature, block one of their other creatures to kill it, and if you're lucky you'll kill them both. It untaps the creature too, which might be relevant for creatures with a tap ability.
In limited, this can be seen as a quasi-removal spell, or last-chance finisher (remove a blocker and gain an attacker for a final push).
If played in standard, this will be pointed at birds with equipment and titans to gain from their attack trigger.
This will be fun in casual decks, even more fun in multi-player (steal an opponents creature to block someone else who is attacking you). I can see it being part of decks with various sacrifice outlets, to make full use of the creature
Gut Shot PR
Gut Shot deals 1 damage to target creature or player
This is comparable to Hornet Sting, in that it will allow a non-red deck to ping something (and makes colour pie enthusiasts weep). Not great in a red deck as it is overshadowed by most (all?) other red burn spells, although the main thing it will have going for it is that it is a 'free' spell, and red burn decks want to be getting their opponent down to low life faster than they are, so wouldn't mind too much about paying some life, and not paying any many might help them to win a turn or two earlier before their opponent can stabilise.
This will be fine in limited, an early pick for sure; it gets rid of mana myr and many early infect creatures, and if used on the latter you're not going to be two bothered about paying two life when your opponent is trying to give you 10 poison counters.
I don't think this will be too good in standard, if Caw-Blade is still popular it could be useful to kill a bird pre-equipping it, but then they will likely have 3 more left to play (unless you play Surgical Extraction, mwahaha).
This could be fun in casual, for similar reasons to limited. It's a surprise ping, there will be some interest in it somewhere.
Moltensteel Dragon 4PRPR
Artifact Creature – Dragon
PR : Moltensteel Dragon gets +1/+0 until end of turn.
Yay, dragon :D
Fairly standard bomb in limited; fairly beefy, flies, and with the bonus of being able to go in any deck. Not a bad play for turn 4 either; same size as Thrun, the last troll. The main downside apart from the potential huge life loss is that, as an artifact, it is easier to kill, particularly in this format.
I'm not sure about this in standard, it might be good for a finisher in a red deck (play cheap creatures and burn early, play this for 4 or 5, even though you have the red, just to get it out earlier, and then you have red land to pay for the ability rather then paying more life).
Seems a fun card in casual for sure. Its a dragon, which is always popular, and one that you can fit in any deck! It does all the dragon-y things too, fly, be big, breath fire, what's not to like?
I really want to see this at some point with lifelink, that would be pretty funny.
Rage Extractor 4PR
Whenever you cast a spell with φ in its mana cost, Rage Extractor deals damage equal to that spell’s converted mana cost to target creature or player.
I doubt this will be played in standard, unless it is put together as the main focus in some combo deck. This will be hard to be worth playing in limited, maybe with some sealed pools, but you'll only have one pack where it will be possible to get Phyrexian mana spells in a draft, so its effect will be seriously limited. There might be a fun casual deck with this, but it seems a lot more restrictive than something like Pandemonium.
Ruthless Invasion 3PR
Nonartifact creatures can’t block this turn.
This looks like it wants to go in an infect deck, I can see it being a finisher in a limited infect deck perhaps, but would help out an alpha strike in any deck.
Not sure about standard, I don't know how often this kind of effect sees play (but if infect becomes popular, it might be played a bit).
This could be quite fun in casual, mainly in swarm style decks, as you can use the one spell to attack all your opponents at once with limited blockers.
Slash Panther 4PR
A very aggressive card, will fit into most limited decks. With the haste it can quite handily take out a noticeable chuck of your opponents life total.
I don't think this will see too much play in Standard, but wouldn't be surprised if it does really. It does seem like a fairly decent casual card though.
Birthing Pod 3PG
1PG, T, Sacrifice a creature: Search your library for a creature with converted mana cost equal to 1 plus the sacrificed creature’s converted mana cost, put that creature onto the battlefield, then shuffle your library. Play this ability only when you could cast a sorcery.
This one looks quite interesting.
I'm not sure its going to be a good card in limited, as you are often going to want to keep your creatures and not sacrifice them, but it could have some benefits, if you have a really really good creature you want to get out.
This could be interesting in standard, I can see some interactions with Vengevine recursion (just gotta find a load of interesting 5 costing stuff...). This is something that looks like it would work well in a black deck, as that can easily get sacrificed creatures back, or potentially in an infect deck to 'grow' the size of your threats each turn. It could also see the rise of a toolbox style deck (or an addition to ones with Fauna Shaman)
This will be very fun in casual, especially highlander/commander decks as a repeatable tutor (think of a deck with many creatures with 'enter the battlefield' triggers...).
Corrosive Gale XPG
Corrosive Gale deals X damage to each creature with flying.
At most this will be a sideboard card. It could see some main deck action if Caw-Blade remains popular, but even then there are going to be better ways to deal with a few birds. It might be useful in limited, more often as a sideboard card I think then main deck, but that would depend on what you usually play against I guess.
Mutagenic Growth PG
Target creature gets +2/+2 until end of turn.
Free pump spell! :D This looks fun. On an unblocked creature, the life difference is the same (you both lose two, they will be losing more though). Better on an infect creature obviously.
This will be amazing in limited, and keeping a land in hand to bluff holding one (in any deck remember) will make combat tricky. This could even make it worth playing Mental Misstep main deck in limited. Really good with infect (any format), and means you don't have to be in green to have pump with infect.
I don't think this will see a huge amount of play in Standard, but I think there will be a few decks that play it, more infect based strategies than anything I suspect. Of course, with a free pump spell there are hilarious quick kills with it (turn one infect creature, turn two give it double strike (there's the single red spell that does it), two of these for a 5/5 with infect and double strike, or for a version that doesn't need any colour mana, turn one Inkmoth Nexus into Signal Pest, turn two activate Nexus, attack with both, pump 4 time (ha) for a 10/10). Free pump is silly.
It will be very fun in casual decks, as I've mentioned its a good one for my random Wee Dragonaughts combo deck, will fit into casual infect decks, and lifegain decks (as will a lot of these Phyrexian spells, but this is a good way to use it).
Noxious Reveal PG
Put target card from a graveyard on top of its owner’s library.
I like this kind of effect, it puts you one card behind, but if you're getting back a really good one it's not so bad. Probably not that great in a black deck (there are better black recursion, but this could be handy if you want lots of non-creatures returning). This could be good in some red burn decks, returning some previously played burn later on to finish the game.
This can kind of lessen the effect of the first ability of Jace the Mindsculptor (if they keep the card on top, its probably not that good or they don't mind you having it, so you can play this at end of turn to put something better there).
It will be interesting in limited, it would be worth playing if you have low good threats you might like to recurse. It might also be decent if you have some really good removal spells that you wouldn't mind playing a few times.
The effect is usually a fun one in casual, most of the spells you play are going to be fun, and this lets you cast them again! :D
Thundering Tanadon 4PGPG
Artifact Creature – Beast
Its a big trample dude :D Quite silly in limited, its a power short of the equivalent for the same (green only) cost from the core set, but can come down earlier (turn 4 for 5 power with trample? Nice, and one hit makes up for the 4 life paid) and put some serious pressure on.
I can't really see it being in many standard decks, apart from some faster ones that might want some 'late' threats, which is a role this fits quite nicely. It's got a decent toughness as well for turn 4 (same as Thrun), so might prevent your opponent from attacking for a turn or two before you put it on the offensive.
For casual, its a big stompy creature, there are going to be better cards, but it might fit into some decks quite nicely.
Blinding Souleater 3
Artifact Creature – Cleric
PW, T: Tap target creature.
This will be a serious skill tester in limited. Blinding Mage is a powerful card in core set draft (although sometimes undervalued, especially if the Magic site draft activity is anything to go by), and this opens it up to any colour. Even though it is not necessary, there will be a temptation to splash some plains, even if this is the only card that might use white, to get more use out of it. The most skill testing will come in a deck with no white sources, as you have to ensure that you're going to stop more than the two life you're paying.
I don't think Blinding Mage is played that much in Standard, this comes down a turn later, but has a bit more toughness so might see a bit of play because of that, but paying the life might not be worth it (perhaps in some combo based decks to slow down your opponents a bit).
This could see some casual play, probably not in white decks as there are better options, but, similarly to standard, could be useful for slowing down opponents in combo, or potentially controlling decks.
Hex Parasite 1
Artifact Creature – Insect
XPB: Remove up to X counters from target permanent. For every 1 counter removed this way, Hex Parasite gets +1/+0 until end of turn.
This card has been dubbed "Jace must die", as it is a colourless way to get rid of a Planeswalker. In limited, its an early threat and the ability may have some use, but mostly rely on what your opponents play, so it is a bit hit and miss. If they are relying on Trigons and other permanents with charge counters, or killing creatures through -1/-1 counters, this will really shine.
In standard, this can get rid of some of the most popular cards played; Planeswalkers, and will probably be its main use, at least initially.
For casual, this could go either way; there are some interesting cards that you want to remove counters from and this would fit in well, but I don't know if it will fit into other decks that aren't built with it in mind, just to tackle Planeswalkers.
Immolating Souleater 2
Artifact Creature – Hound
PR: Immolating Souleater gets +1/+0 until end of turn.
D'aww, it's a mini version of the Dragon above :D
Good in limited for aggro based decks, or metalcraft ones. I think it might squeeze its way into a few red decks in standard, where it will come with a high risk (if unblocked, you can pay a load of life for quick early damage). Similarly, it looks like something that would be fun in some casual decks, where lifegain can be more popular (depending on the group really), although it is a creature that is quite easy to get rid of (one toughness artifact).
Insatiable Souleater 4
Artifact Creature – Beast
PG: Insatiable Souleater gains trample until end of turn.
Even without the trample this is very aggressively costed at 4. The main problem is that it is as easy to destroy as the card above (one toughness artifact creature). Would still be worth going into most limited decks I think, even if you only get to swing once and pay two life for the trample, you're going to be distributing 5 points of damage around one way or another, which isn't that bad.
Can't see it making too much of an impact in standard, at the most it would be the top of a curve of a very aggressive deck, but that would be it I imagine.
This seems fun in casual along with a deck based around the '5 plus power matters' theme on Naya from Shards of Alara, as it comes out earlier than most other creatures with 5 power, and doesn't have any colour restrictions.
Artifact – Equipment
Equipped creature gets +1/+1 for each Swamp you control.
This can only realistically go into mono-black decks, or at least a deck where swamps are the main land played, otherwise the creature will be unimpressive, and it will be hard to equip it after the token dies. This is almost comparable to Bonehoard in that it costs 4 and has a variable bonus, but this bonus is controlled by you a lot more. I do quite like this card, along with a number of other black cards in the set it is looking to make mono-black a possible deck choice. I'm not sure how will this will fit into an infect based deck, as the 0/0 creature would mainly serve as a defender, but at the same time you might just want to strap it to something with infect to make it huge (I like thinking about this on a Phyrexian Crusader, turn 4 to play and equip and attack with a 6/6 first strike infect, protection from red and white, pretty sweet).
This will be interesting in limited, its a fairly decent equipment if you are playing enough swamps. In standard, it will probably have to be in a mono, or mostly, black deck to get the full effect out of it (otherwise you may as well just play that scythe that does this effect for any basic land you search for).
It looks like it will be quite fun in casual, I have a friend of mine that has built a deck around the shade (B: +1/+1) mechanic, so this seems right up his alley.
Pestilent Souleater 5
Artifact Creature – Insect
PB: Pestilent Souleater gains infect until end of turn.
This is mostly unimpressive, it might be OK in limited because it can come deal a fair bit of infect damage (compared to a lot of other common infect creatures anyway) and if you're no infect its an overcosted 3/3 that can occasionally be made into a decent blocker.
I doubt it will see any play in standard, but there might be a deck that can make good use out of it. With casual, again, there are better creatures.
This is really kind cost that I would have loved to see on Vector Asp, instead of the single black, which is somewhat awkward to play when you are trying to play a fast infect deck.
Artifact Creature – Horror
PU: Change a target of target spell or ability to Spellskite.
This card is somewhat interesting, it can allow you to redirect a kill spell once, maybe twice, and blocks while it does so.
In limited, it may as well be a wall (two costing walls were quite popular in Rise of the Eldrazi), that could occasionally interact with some of your opponents spells.
In standard, this might be funny to side in against an aggressive deck, probably a red one; block the smaller dudes, redirect burn spells to it, until it annoys your opponents too much and they get rid of it.
In casual, it's the kind of card you would play if you like bugging people by moving spells around. Not that that's a bad thing...
Trespassing Souleater 3
Artifact Creature – Construct
PU: Trespassing Souleater is unblockable this turn.
Fairly decent in limited, its a grey ogre that can become unblockable if you like. As its doing 2 damage each time, and the unblockable costs two life if you're not playing blue, it can't win a game on its own, but for 3 mana in limited, its still fairly decent.
Probably not that great in standard, but it might be useful if a deck is built that tries to attach all three of the swords to it to use all the abilities (unblockable means they defiantly trigger, barring shenanigans).
This gives unblockable to any colour, so could see some abuse in casual decks (where a deck that tries to attach all 5 of the swords to it would be more likely than all 3 in standard, and a lot more hilarious).
...and that's the end of the review. Hope you've found it interesting, sorry if I rambled on a bit, I'll end with some thoughts about the mechanic in general, and not any specific cards.
In general, you mainly want to be playing these early on for huge tempo gains, but if you don't have the correct mana, late game you might be reluctant to play them unless they will hugely help towards winning, and in some cases your life might be so low that you can't play it at all, which can potentially make them a fairly bad top deck.
As these cards allow for cheap and sometimes free spells, they are going to see a lot of play. The downside of this is that it makes infect slightly worse, as they can play 9 of these spells without caring what you play as you're not trying to kill them with life loss.
If they are played heavily, it might make games go quicker as everyone will be on much lower life totals faster on through games, and could make red burn decks more popular.
In drafts, picking these will now be in the first pack, so if you pick enough, you aren't necessarily going to be set in a colour by the end of the first pack, which can be handy as it leaves your options open for the rest of the packs.
"Free" mana is often very powerful, and I think these cards are no exception. They may even make control decks less effective (only have one counter a turn to counter two spells? You're going to let a lot slip through).
I don't know how well these will fit into limited decks, but some will see some consistent play for sure. More often then not I suspect people will be playing around the threat of some of the spells as opposed to actually playing or interacting with them.
They will be seeing a noticeable amount of play in standard, hopefully not enough to make the format too warped, but I'm fairly confident that Wizards have done enough play testing to ensure that it's OK (hey, stop laughing! I'm sure they play tested with Jace too...). A couple of the cards have already had some interest in other formats, legacy being a prime example (free counterspell that's not Force of Will that hits a lot of the cards played), and some other cards are fun enough to make an impact in a large variety of casual decks.