I came into Gamestop wondering what to get, I came out with what I now know to be one of the best tactical shooters out there, only bested by it's Tom Clancy cousin, Rainbow Six Vegas. The Controls are polished, better than recent games such as Frontlines: Fuel of war and Quake wars. It takes about 30 mins. to an hour to get a good and satisfying knowledge of the controls, but once you do, it's a blast.
The Campaign is hard, but not hard enough to make you want to quit. Also, it has a decent storyline, which is worth listening to. The AI is definitely not the best, but at least the games not easy.
The Multiplayer is definitely the lasting contribution and will have you picking this game up months and even years after you beat the campaign. It's competetive, and I surprisingly found lots of people to play even though I just bought this in January.