Can't we just say they're both great games and get on with it?
If you own just a 360 or PS3 it doesn't matter which one is better. If you own both then you have two great games to choose from (which is a good thing).
-edit-
And since this is a topic that is just asking for trolls to chime in just a warning I'm watching this and other topics like it closely. Please keep things civil and we can actually keep the thread open.