Ok, to start with: I don't actually own the game. However, I have played multiplayer at a friend's house, and I was pretty impressed. Considering the most modern games I own are Portal and Team Fortress 2 (both released in 2007) the graphics and physics blew me away. The action is, comparatively with TF2, very balanced, and the weapons are pretty interesting too. I like being able to customise my class extensively as well. I also know the basic storyline of the game, and think that with some character development it could make a nice action film. However, there is a lot of shooting, and although not as graphic as Half Life 2, just as realistic. There is some cursing and drugs, but the latter is only in storyline, and the cursing is only in storyline mode, or if you're playing online.
Shame my parents won't let me get it. Very fun, can't wait to play it again.