Note: turning off Vsync is fine if your game runs < 60fps, but if you're running 100 + you may run into problems with vsync off.
One notable area with problems is the Boss in Mithalas. (his suction attack won't work)
So yeah, if you can run the game fine with Vsync on, keep it on.

If the game only runs with Vsync off, you may have issues with your video card. Its better to update your video card drivers in that case.