[quote name='Bill Mcdougal']So what are the benefits to the PS3 version compared to the 360 again? I just don't like getting multiplatform games on PS3 and prefer them on X360 for some reason. If it's just an extra steam copy, I might go 360, as I don't think I'll need to play the game on multiple platforms.[/QUOTE]
The benefit isn't just the PC copy...having it connected to Steam also means that the PS3 version will include the same sorts of additions and updates that the PC versions of many Valve games get for free. For example, the PC version of Portal has a new ending, added after release, that the console version does not. Then, there's the free DLC that otherwise costs money on Xbox360, though nothing as far as DLC has been promised yet for Portal 2 specifically that I know of.