MAG it's more of a team tactical game with lot of objective to do.
Domination - 256 players, attack/defend. Two layers of defense, all hell breaks loose when the first layer falls.
Acquisition - 128 escort style game mode. Steal 2 prototype transports and bring them to the extraction zone.
Sabotage - 64 player. Control 2 points for a certain amount of time, then a demolition objective is revealed which you must destry, very different from MW2 where you just run and gun most of the time, you can run and gun on MAG too, but you won't be helping your team WIN. For me I've been playing since beta 1, back in September of 2009, just can't get enough of it haha.