I just tried chess.com's live chess. Overall I'm impressed with the browser gymnastics that chess.com is doing. I played a couple of games and, for the most part, it was performing pretty well. At one point, my firefox 3 usage shot up to half a Gig... major memory leak someone? I am sure they are trying to figure out how to fix this.
I gotta say, though, that the UI doesn't feel as responsive as Internet Chess Club + Blitzin. So for now, I'll still be sticking to the good ol' ICC.