I've used my Logitech MX518 for about 2 years now with not trouble at all.
Whats the point of buying a mouse with 3000DPI when your actually going to set it back to 1200 or 1500, especially for FPS games, the less sensitivity the better.
Also regarding the feel of the mouse, this is going to sound gay but everybody has their own preference when it comes to a mouse, the way it feels in your hand.
The point i'm also trying to make is that buying a mouse worth R1000 isnt going to automatically improve your game...
I would say go with logitech, but as i said everybody has their own preference.