well i have a 360 and ps3.
i bought it for 360 because,it was the only version available for consoles.
1 year later,ps3 version is released,i like that version better...didnt buy it,because i already have it for 360.
this is the case with many people im sure.
Bioshock 2 will be a multiplatform release and ill get it for ps3.it will sell well over a million on ps3.