This set has some pretty nice cards, but I'm hardly familiar with it. I like Measure of Wickedness because I used to always play Donate/Illusions back in like 2002-2004 and it's a less broken and more black take on the same concept. Plus it seems like it could be fun in multiplayer to see people trying to pass it around and not lose the life. I also like Freed from the Real. Being able to shut down an opponent's attacker or utility creature is nice. Being able to turn any creature into a Horseshoe Crab is even better. A card that can do either of those is great.
However, despite being the biggest fan ever of Tendrils of Agony (which I've decided is the greatest card ever--even better than Dwarven Pony), I'm also a fan of Arcane Laboratory. And despite usually spurning flip cards and the slough of legendary creatures in this block with crappy names, this one is basically cooler than Arcane Laboratory. So I nominate Erayo, Soritami Ascendent.