I prefer Liberty city as it actually feels like a city first and foremost, and a playground second. The ridiculous ramps stuck all over everything in GTA:SA were just a bit over the top.
Between the car control, ragdoll physics, control and visuals, GTA 4 is easily the best GTA by a huge margin. I enjoyed GTA:SA alot but it was almost like a cartoon compared to the rest of the series.







