Apart from the occasional frame rate drop, texture pop-in and alien critters getting stuck in the scenery, the game has been really stable for me. No big problems whatsoever. Have yet to try online though.
The single player campaign already made this game one of my favorite console shooters of all time. Thanks Crytek, for putting in a real single player campaign instead of the <4 hour, handful of mission campaigns developers throw in these days. The story is ok as far as I'm concerned, even though it borrows elements from other games/movies. Who needs an excuse to run around lush environments, killing off soldiers and aliens anyway?
Oh, and it's the best looking shooter for PS3 as well, the only thing that is similar is Killzone 3. I was really tempted between KZ3 and Crysis 2, but decided on the latter. No regrets so far.
In case anyone's wondering: playing on a 80GB Fat PS3, combined with a Full HD 40" LED Samsung LCD and a Harman/Kardon AV Receiver.