The only real difference between the PC and console versions is...
The PC version allows players to crank up the view distance, detail settings and other visual goodies since they (we) have the hardware to do so. However, the major drawback to the PC version is it is horribly optimized for the PC compared to consoles. So, even though it may look better visually... It doesn't run as well as it should (like on the console) and this almost makes playing it on the PC pointless. The PC version has massive frame rate spikes (60-20-45-60) and a lot of micro-stuttering for a lot of PC users whereas the console is rock solid at 30FPS because of HDTV limitations.
Also, one of the biggest flaws of the PC version is the R.A.G.E. (Rockstar Advanced Game Engine) engine was never designed with high-end PC hardware in mind. So, it only really works well if you use console equivalent settings which again, defeats the purpose of playing it on a PC.
I can run GTA IV with high texture settings (console is medium), but I still have to set the view distance, level of detail and traffic density to the console levels if I want fluid game play... And I'm using an i7 CPU with a 4870x2 card with 2 GB of VRAM!
The worst part is the final mission -- doesn't depend on whether you pick "Revenge" or "Deal" -- Is bugged because anything over 30FPS makes the Quick Time Events (where you have to press specific buttons) unresponsive because the game engine was never designed to go above 30FPS! So, you have to either play the entire game with 30FPS via a Commandline.txt, or switch to 30FPS during the last mission which will feel very jerky if you've been playing the entire game with 60FPS previously.
As far as actual content differences, the PC version has full three-piece suits as part of Niko's wardrobe whereas the console versions only give him sport jackets and slacks options. R* did this to give PC players an exclusive.
The other big difference is you can have custom music tracks in the PC version by placing your MP3s in the Rockstar Game Directory. So, whenever you are riding around in vehicles you can "tune" the radio station to play your own collection of music. It's actually pretty cool because it makes the game play experience more personal and dramatic sometimes.
So, I would just play it on either Xbox 360, or PS3 and skip the PC version to be brutally honest.
The game is still the same. It's not like the PC version is more complex, or complete so-to-speak. It's still the same game play mechanics, glitches, story line, etc.
Does that answer your question? This post has been edited by GTALegacy on Thursday, Sep 20 2012, 02:46