SA was wayyy too big. Absolutely huge, though it was kind of cool that it had many different areas - the hillbilly town was rad!
Best thing about Vice City was how the gangs worked. If you upset a gang, every time you went near their hood, they'd chase you, shoot your tyres out and attack. If you were attacked and a gang you were on good terms with were nearby, they'd help you out. Or at least I think that's what happened, quite some time ago now!