It's not even a question of which is going to sell more. ME2 is a sequel to a pretty well-liked game, and by all accounts it's way better and more mainstream in some ways than the first. Advance buzz has people saying it'll be in the GOTY conversation, even though it's coming out in January. MAG is a new IP with mixed feedback from the beta and in a genre that 1. doesn't sell quite as well on PS3, though well....and 2. is up against the biggest FPS there is right now in COD. Will people bother buying another FPS so soon when they have a really strong one already that is obviously going strong? I think MAG will have a decent debut but then will drop off pretty hard. I just don't think word of mouth has been strong enough for it.