I have the model before, the MX Revolution. and it's the best mouse I've ever had.

I've got my buttons set, the middle (not wheel) to Menu, the thumb Up as F5 (refresh) and the thumb Down as Back.. the side wheel is to scroll windows...

touch my MX and you will die. I'm planning on a MX Performance when this finally dies (had this 3 years now and, nope, no signs of death)