i think you'd have to be running with gSync at 1440p or higher to really say it looks a lot better, I played with the pirated PC version for a few minutes (playing the PS4 campaign on and off for months now) at 1440p and noticed slightly sharper edges but not much else, my video card is a 680 so i can't push video details all the way up unfortunately and get high FPS. Obviously if your GPU can handle it you can push better than the locked 30 fps of console, but thats never bothered me.
Grand Theft Auto V Face-Off: PC vs. PS4 | Hardcore Gamer
Personally I'm just going to wait and see what the modders do, some russian guy has hacked the texture files but the ENB guy (sweetfx) says he is not going to mod the game because of the DRM. Also the game will be $10-20 this fall on PC.