Bingo...migo said:Most PS3 owners also have Windows PCs, so it's not like PS3 owners haven't played it, they just haven't played it on PS3.
As far as combinations go, that's probably the one that most PS3 owners have (PS3 for the PS3 exclusives, PC foe the '360 exclusives'). That said, there's probably a large chunk of PS3 owners that don't also have a PC, so they're going to be the only real audience this will have.
Though I do wonder how well Mass Effect 3's going to do on the PS3 if it's a simultaneous launch. Sure XBOX owners are more likely to get it for the 360 because it's available for the 360, but I think (for the most part) the PS3 and PC versions are going to share a lot of common ground with potential customers