Alone that makes the mouse unbeatable for me where she has given me some problems. My first mouse (a few years ago bought elsewhere) was the old version which now and then jumps around when you click (amazing!) And sometimes has detected the end of single clicks as a double click. From the build quality of Logitech, I personally am not so confident and I'm certainly not a Logitech fanboy.
But for my hand, the shape of the mouse is just fantastic! I simply asked the ring finger button on middle mouse button, thus I can, for example, very easy BROWSER Close tabs or links in new tab OPEN! Unbelievable !! Yes a very simple function and of course different possible but that's what you do now times> hundred times a day! That's why I want to use another mouse more.
Why are not there more mice with this ingenious three finger mouse buttons design?
Now for the negative:
The first version had bug in the firmware and can not be upgraded as well. The current version works just fine.
The "precision" not up to scratch. The only adjustment is that works for me 1200 DPI. It is adjusted higher will only increase the speed under Windows and pixel skipped! What's the sense of it, please? It should "subpixel" accumulatively for the highest precision when selecting items to be but it's not, unfortunately. At 1200 dpi but it works ok. Of course I have "mouse acceleration" off as a gamer in Windows.
The "block number" I hardly use the other hand, although it offers many possibilities. My MMO times are now times over.
Conclusion: The best mouse, but not perfect.