I own this game, however, I found it lacking. There are quite a few new weapons, vehicles, and gameplay elements in general. But, honestly, its just more of the same. The levels are darker, so what? There are new armys, and..? (Which I want to mention are quite literally the same team as the ones that come with BF2.. just with different uniforms.) New vehicles.. heck yes to that. New maps, ah.. they are so-so.
So.. unless you just want the new extras, I would not suggest buying it. However, if you are into that kinda thing, go for it!