I don't play console so if I get it I have to wait for the PC version. I've only played GTA 4 and the Episodes. It's fun for awhile then I end up driving around the city wrecking into stuff and evading cops until I get bored of it.
As for console vs PC, PCs definitely cost more, but they last a lot longer (if you buy quality components) and when you buy a new one the old one still actually works so you can sell it and make a bit of money back. The Xbox 360 and PS3 are useless piles of garbage and as far as I've seen they never last that long. And of course the outdated hardware so the graphics are limited. I like using the keyboard and mouse for FPS style games too. With GTA4 I switch between the keyboard/mouse and controller depending on if I'm doing a shootout in a mission or just driving around. You an always find the good and bad between two things. I prefer the PC in this case.