Having received both the PS3 and 360 versions of the game for review, Joystiq as reported that both versions are, in fact, identical.
So, what happened to the exclusive PS3 content? Joystiq has speculated that the additional content could be the "Whored Mode", SR3's wave-based co-op multiplayer that features in the PS3, 360 and PC versions of the game - publisher THQ has not commented.
Find out what Daemon Hatfield thought of Saints Row the Third in IGN's review.