Ultimately, there is just too much to tell about GTA IV; it's a game that should be experienced firsthand, rather than explained. There are minor discrepancies between both the PS3 and 360 versions with load times a bit shorter and pop-in less frequent on the PS3, and reportedly exclusive content on the way for the 360; but no matter how you look at it, you can't go wrong with either version of the game-though there has been reported issues with the PS3 version online.
Strategy Informer have tried to make a case that GTA IV isn't a perfect title, and although it isn't, it's one of the most complete experiences to date. So if you've actually read through this, and don't have the game, they appreciate it, but seriously, just go buy it already.