I've just got it on PC (after playing the first 2 weeks on PS3) to see what it's like (and try some mods to see how game changing they are).
Although I haven't layed much PC yet, my personal view is that it's better on PC. Although I need to adapt my driving style so that I don't keep hitting the AI on the opening corner (sometimes a bit too aggressive is me), I just seem to be able to drive so much better on the PC. I've been learning to play w/out TC (on medium at the mo) and on the PC I just seem not to be spinning so much and I'm able to get the power down much earlier than on PS3 (not sure if its just the controller or what) (I use the same button config on PS3 and PC [have an old Mad Cats PS2 wireless controller on my PC via a USB connector]) (Thinking of trying that controller on my PS3 to see if any different). The mods certainly add loads to this game and it's something that's great as you don't have to wait for the developers to change the game like you do with PS3/XBox.
Having said that though, I'm more likely to play more on PS3 than PC but that's more down to the fact that I work from home and when I've finished for the day I turn my PC off and hardly ever go on it at night time. The PC will end up a nice little lunch time pleasure for me.
