I really like doing this; survey is here.
Ruthless Disposal-this is a good card. The cost is very, very high but on the other hand, there are only two creatures in the game of Magic with toughness over 13 (barring BFM, of course). And it's pretty easy to find a deck to fit this card in, I think.
Hanweir Battlements-any card that needs another card to realize it's best form has to be marginal at best. If the Battlements didn't have the third ability (which is how one should approach it) it would be a Flamekin Village and nobody's beating down the door for that.
Prey Upon, EM edition-I really like the art, especially in the way it evokes the last Innistrad set. After that, the card is fair. Green removal isn't great but it exists.
Identity Thief-while I still really love the art and the name, the card is just fair. It needs something else to be good and that something else that is good is a bit narrow.
Smoldering Werewolf/Erupting Werewolf-I dig on SW's art but not EWs to much, so I split the middle to good. I rated the play value poor though: I just don't see any reason to play this card, beyond Limited formats and even then, the stats are pretty weak, unless you invest 10 mana. Marginal because this does have a little use in Limited.
Ulrich of the Krallenhorde-This was the first time I felt the art was marginal. Gold card with gold border and a figure that's a bit wonky on proportion? I'm now starting to reevaluate every card art... In the end, I gave this a fair rating. It does do some powerful things but you can't control it.
Tattered Haunter-here we go again, blue art with blue border. Kinda looks like just a big tube with chains coming out of it, too. I didn't like the flavor text either; the Nebelgast was not only new data, it wasn't very helpful in worldbuilding since EM is about Emrakul wrecking things. That said, a 2/1 flier for 2 is not bad, so it got a fair rating.
Blessed Alliance-I think this card is excellent. Good at 2 mana, but amazing at 4, I really like this one. Except for the white on white art.
Graf Harvest-While I like the art and the name, I don't see any reason to play the card. Poor.
Sigarda's Aid-that aid looks like it's coming too late, doesn't it? But the flavor text makes up for a lot, and the ability on this card is outstanding for its cost. It will take a specific deck to house it but it will be a great support card when that deck is found. Rated good.
Eldritch Evolution-Really not enamored with this art. I'm also not in love with this card. It's good but it isn't amazing.
Extricator of Sin/Extricator of Flesh-Marginal. 3 mana for two creatures isn't bad but it isn't great and unless you a) hit Delirium and b) have it survive a turn, it's not very awesome.
Contingency Plan-Poor. Getting to dispose of any chaff on top of your deck, plus adding to certain strategies isn't bad but as a sorcery? I'd rather do something else.
Woodcutter's Grit-I finally get a green card that doesn't center around green colors and it looks like THIS? Ugh. It's like someone blew on all the ink as it dried. That complaint aside, +3/3 and hexproof for three mana is a solid deal. Fair card.
Field Creeper-yup, I still love this art. It's a maginal card at best but I think I'm giving it a bump because of the art and flavor text.