I hated SA, it really was filth compared to VC.
The location of vice city was stunning (fine the graphics were never groundbreaking, but in the day they were not ugly, SA felt like a massive step backward).
The gunplay was clunky and boring in VC, but still somehow fun enough to not overly bother me, in SA they managed to kill it by trying to fix it (the leveling system was pants on head retarded, it's a GTA game, I have no intention of ever grinding skills in a GTA game).
It was a real gangster/mafia scenario in VC, SA felt, to me at least, like another faggy 50 cent "my niggerz ***** ho please!!" thing, which is at best a stupid steriotype to reinforce. The whole homies thing bothered me as well.
Both had fairly decent soundtracks, but VC was had the best radio stations if I recall correctly. Everything just fit, it was the 80s so you'd be listening to peace sells or video killed the radio star. The SA one wasn't bad by any means, it just wasn't as good (one of the few things they did right in SA as far as I'm concerned).
The map for VC was infinately better than the SA one, SA was such a big space with nothing in it.