I've played a little bit of it. There's actually a bigger thread in the Xbox 360 forum, which I find kind of weird since CS was originally a PC game.
I tried to get into a game of Arms Race last night, but it wouldn't connect. Not sure if no one's playing it, or if something was wrong with it. I did manage to get into the classic games, but didn't play much. I'll probably get on more tonight though after work.
-- if you wanna play.