It's sorta like an RPG with some strategy worked in with MMO elements, sorta like an MMO except you don't have to worry about all the crap that comes with you traditional MMO
one thing some people don't like is that, even though it takes a long time to get to lvl 20, you can only get to lvl 20 and from then on you have to rely on your stategy with your skills and attributes
definitly get Battlefield 2, and maybe Halo