Since this site is the spiritual successor to PCGamer.com...those of us who made the transition would most likely be buying it on PC for the first time, as opposed to buying it for the PC in addittion to a console version.
To tell the truth, I have yet to play San Andreas on PC, but I had absolutely NO problems with either Vice City or GTA III. The reason that it is harder to get games working on the PC as a platform is the fact that there are thousands of different hardware combinations possible..whereas with consoles, for each specific model, the hardware is exactly the same on all of them. the good thing about PCs is the ability to patch the problems.