I have the mouse just to get used a week in a job in use and still need time fully to it, I finally used for years almost every day a standard mouse. The hand position is quite different and the muscles are otherwise claimed, it takes time to get used to. But it is getting better. I make the points that I want to click faster and more precise. And would say that I have fallen to about 80% of my previous speed. Initially, such a strange, unfamiliar Klotz was the mouse in my hand, or the hand at / near the "block", but that feeling changed after a few days in a pleasant, familiar handling.
Every now and then I came first with my hand edge the mouse around when I wanted from the keyboard to the mouse. Well, the thing is just higher. Just like that lift when the mouse pointer must be manually scrolled behind, is difficult without simultaneously pressing a key. This is easier by the mouse is tilted outward and then pulled or pushed.
The keys are arranged well and clearly separated and can be assigned with sufficient functions. The mouse speed is optimal for me to use the fastest setting, and some of my colleagues call my mouse as gerbil :-)
The only criticism, but not the star deduction is worth for me, is the material at the thumb Kuhle. This smooth coated material ensures that I'm sweating or is somehow slightly greasy another reason his thumb. As would "form follows function" have been appropriate. The same material as the rest of the mouse and already I had nothing to complain about. This looks likely but not so stylish of how this brilliant silver. Well is to get over.
Addendum 27.02.2013:
Mouse has recently complained because the scroll wheel is no longer working properly. Whether it was on the mouse itself or on the receiver, I can not say. The mouse has been replaced by the dealer.