I've got an Xbox but haven't really tried the PS3 much, though my step-bro does have 1 and personally I prefer using the xbox controller, and I think the Dashboard menu has had a lot more thought put into it than the PS3 menu. But other than that, the PS3 comes with rechargable controllers, built-in wireless and bluetooth and you don't have to pay to use the internet...
So even though the ps is more expensive initially it works out cheaper in the long run cos you have to buy all that stuff I mentioned above separately for the xbox. Kinda jammy. Still, im happy with what i've got.