We've run Blood Artist for a while now and it's been pretty darn good. He regularly does more burn to face + Lifegain than a Lightning Helix to the dome does. It has provided great reach in BA and helps it alot in the aggro mirror where black is usually in trouble. I've seen one game where it's did more than Sorin's Vengance for only 2cmc (vs. G/W tokens). It draws removal quick lately, which is fine since he puts you ahead as it's card parity, often mana parity and a 2 point life swing in your favor (except against white Exile stuff, which is still parity). And as always, he can carry a sword. Dark Confidant, Bloodghast, and Dauthi Horror are better at the 2 spot, but after that it's pretty debatable here.
http://forums.mtgsalvation.com/showthread.php?t=385729