Actually, the last patch fixed most hacking (it was pretty bad before, now you barely see any hacking at all, especially on PunkBuster servers, or servers with an admin).
Single player for Crysis is the BEST I've played (make sure to run it 32 bit on your computer though, it's a bit more stable); a bit easy if you've played other games, so run on Hard, if not Delta. The suit modes are a bit shallow, but still fun. Basically, go anywhere you want, do what they tell you in anyway you want, when you want, where you want; very nice SP.
Multiplayer, ignoring the hacking problem that was so common before patch 1.2, is okay. It's somewhat similar to the battlefield series (especially one map/mod, called El Alamein: it's based on BF2). The best server is unquestionably the IMP or TFD clan servers: they kick cheaters, exploiters, and people who play cheap. (By the way, there's another patch on the way; I believe they said it was for the autodownloader for multiplayer maps, and team deathmatch).
Also, you should know it takes like three seconds of firing at someone's head to kill them; the armor is insane (I think that's good: at least better than some games in which 2 or 3 shots kill you). If your accuracy isn't perfect, you'll find yourself dying a bit.