Tough choice, but as much as I love Just Cause I'd have to say GTA because of the missions. Atleast in GTA the missions and side missions don't get boring and they are varied. In JC the main missions are fantastic but the side missions are all the same, they're either liberate a village/liberate drug cartel/meet this bloke pick up this and bring it back/find this vehicle etc etc. No matter where you go in the vast map in JC the side missions keep repeating themselves and I found that I kept doing the same mission maybe 3-4 times but from different areas of the map. I agree the graphics of JC win hands down, the vehicles rock (although the driving engine could of been tweaked a bit more) and the stunts are crazy (I love getting a helicopter taking it as high as I can go then jumping out and free falling back to earth, I timed it from jumping out of the helicopter to actually landing and it took an amazing 3mins 32 seconds!!!! (real time)) The game is HUGE but this, is almost it's downfall, there isn't enough variety in the missions and when the main missions are completed (6-7 hours) there isn't much else to do. Don't get me wrong I love JC but GTA just wins because of the variety of the missions (for me anyway).