Well FABLE 2 is rather an elite-gamer game with deep gameplay. It will appeal to a smaller audience.
LBP on the other hand benefits from its hype and also the fact that PS3 community is still expecting some "flagship games" (Like Killzone 2 and MGS4 which finally arrived after several delay).
LBP will win. But this thread is nonsens because this isn't games you can compare 
Evan Wells (Uncharted 2): I think the differences that you see between any two games has much more to do with the developer than whether it’s on the Xbox or PS3.







