@Dodece,
That is an interesting point, but I think the lack of BC is easily the larger issue for the PS3 of the two. Perhaps I am a bit bias in that regard as I am one of those people who loves the GTA series but refuses to buy a PS3 without BC, its worth mentioning that similarly I currently don't see value in buying a 360 due to PC library overlap...hopefully one or both of those things will change.
Either way you are correct that I hadn't really considered it. Now more than ever I am extremely interested to see how GTA IV software sales break down amongst the two consoles.








