Firstly the xbox 360 is only selling more in USA because of the cheap 4 gig version, being lapped up by many parents for their kids. If ps4 had an equivalent, shaved $50 off the price, believe me the ps3 would be selling like hotcakes.
Ps3 was significantly more expensive than xbox 360 at release, not to mention the 1 year head start it had. So if all things were equal and ps3 released alongside xbox 360, being priced evenly, the ps3 would be ahead by a few million. Globally ps3 would have been ahead by 15 million plus, easily. Ps4 will probably be the first to release, and at a price similar to xbox 720,so expect ps4 to sell more .,







