I was suspicious at first, after reading the review which praised it in a lot of ways, there was talk of some slowdown, and of a diluted GTA experience.
I must say I was pleasantly surprised. I've barely seen any slowdown or jerkiness. Tiny hints of it when the screen is full of cars and people AND there's smoke or an explosion going on, but it's hardly even noticeable.
Regarding frame rate I'd say its the very same as the Xbox version of San Andreas, because even that slowed down when the screen was cluttered.
Anyway, the game is more like GTA 3 and Vice City, with a couple of San Andreas bits thrown in. The graphics and amount of people, cars, and things to do is right up there with Vice City.
It's actually amazing to see a full 3D city running on a handheld. And the sound and radio stations are all there.
The story seems a bit generic at the moment though. Mafia type guy, doing stuff for the 'family'. Some missions are simple drive around affairs, but there's some decent variety overall in what I've done so far. Acting and cut scenes are just what you'd expect from any version of GTA.
Drink Up Ye Cider. 
