It's a very good game. I'm a realism fanatic, and found this to be to my liking. THe movement speed is close to normal human speed, so the game doesn't play like Quake or Counterstrike. Similarly, death can come very easily. You have many opportunities in the storyline arc in this game, from being a tank commander, a commando, a regular soldier, and officer in charge of a squad, or a helicopter pilot.
The graphics are also quite nice, and you really have an entire island to play around in.
The multiplayer needs some serious work though. The basic game doesn't have a server browser at all (requires GameSpy) and you can't join a game in progress. So if a game lasts 30mins to an hour, you have to wait that long to actually join and play. You can't even join and ghost around. If they fixed that, the game would be really something.
So, get it for the single player, and hope the multiplayer evolves into something better (because it is nice when you get in a game).