The full release is definately smoother than the demo was. But i'm still addicted to cod4. Once i finish that campaign i'll probably get back into crysis. Also, if you are going to get the game, hit up Circuit City and get their weekly add and have best buy price match it. It's on sale for 39.99 plus you get a 10$ gift cert on top of that.
edit 2: buy cod4 its also on sale for 39.99. awesome game and the requirements are WAY lower than crysis.