Hey,
The GTA games are different to just about every other game ever produced. They give more freedom, the maps are bigger and the game play is pretty realistic.
I've got all the games from Vice City right up, some console some PC. I haven't pre-ordered this release, but I'll grab it at some point, I'm after the PC release (which I'm sure will come in time).
Do you think it would look better on the PS3 than it would on PC?
It depends on your PC's spec. For most people who don't know too much about computing, and don't know how to fiddle with hardware, I'd advise you to buy the PS3 version, real noobs should buy the XBox 360 version =P. Otherwise if you have a recent graphics card I think you'd probably be able to get good picture.
-Luke.