I guess 2:1 is a lot, so are we taking US sales or Worldwide? If it's US sales then I'm kind of surprised, but if it's Worldwide then I'm not, because the game remained PS3 exclusive in Asian countries. Most people I know talked about buying the game for the PS3, even when they already owned an Xbox. For people who own both consoles, the only reason to buy the Xbox version would be for the achievements, but that seems like kind of an insignificant reason. But then again, I know if I was going to chose, I'd pick the PS3 version simply because of the quality, less discs and even the familiar controller- reasons that also might seem small to others. People choosing the PS3 version because of nostalgia/home console makes sense, as well.