Well, the first video review for Grand Theft Auto IV is finally here, and it is from IGN. The written review also has the "better-looking version" section. Lets take a look.
"For those wanting to know which version looks better, the edge goes to the PS3. The textures and framerate are comparable, but the PS3 has far less pop-in. The 360 has richer colors, but the PS3 has better anti-aliasing making it look a little cleaner. Because GTA IV can preload onto the PS3 hard drive, the in-game loads are faster. Don't worry Xbox owners, the load times are rarely more than 30 seconds and don't occur very often. The slight visual edge goes to PS3, but the 360 is no slouch. Either version will do you proud."Yeup, the PlayStation 3 won that, but I'm sure both versions of the game play exactly the same. Tuesday cannot come any sooner.
[Grand Theft Auto IV IGN Review]