The difference is $$$.

Over the course of the past year or so I have seen many comments and posts about how come the PS3's graphics aren't far superior than the XBOX 360's even though it has the so called "Cell" processing chip and is light years ahead in technology than it's counterparts.  Well I know I can give you one good reason.  Money!!

Developers would have to have seperate groups of designers just to develop games that they really want to develop for the PS3 so that they could up the ante on the PS3.  They know the capability is there but the money is not.  That's why you see games being made on the same level as the 360's so they can save a ton making one game on two consoles and make even more money in return. 

Now just imagine if they had seperate studios for each system.  I think you would see longer games, possible slight increase in graphics, more animated and involved AI, and a mass abundance of on screen animation going on.  But the thing is, you won't, at least not yet because of that thing called money.  That's why you'll only see this kind of game coming from exclusive Sony studios or game companies that have exclusive rights to them. (Ex. Konami, MGS4). 

I think once the some of these studios start seeing games come out and other studios start getting involved with exclusivity then you may see games that you will want to see on the PS3.  Man I can't wait for those days to come.  Until then I'm enjoying the games that are out so far and it's only into the first generation of it's life cycle.  Let me know what you think.