If you like good game play and large scale fights and decent teamwork, Battlefield 3 is the way to go. If you like repetitive game play and smaller, close quarter combat and the same game you have payed for, 4 other times(Call of Duty 4 and every CoD game till now if you bought them), then you would probably prefer MW3. I have been a Battlefield fan since 1942 came out for the PC years ago. And I used to be a CoD fan till Black Ops came out and I got tired of spending 60 bucks for almost the same exact game. I think you would probably play BF3 more often than MW3 over the course of a few years. A Battlefield game has always had a habit of surviving for many years before killing over to a new game play style and a new Battlefield game.