For the money I bought it for, this is absolutely not Logitech quality and not Logitech ergonomics. It seems that finding a mouse with at least 4 additional keys conveniently located on the LEFT, like the g500 or the old Razer Mamba was, is simply unrealistic. Its pros: - narrow - many conveniently located keys - good sensor - Logitech software Got cons: - if you close the bottom cover, the legs are at different levels. As a result, the mouse staggers. Perhaps the jamb of the assembly of my particular instance, nevertheless, I had to remove all the weights and the cover because of this and still pick out one leg - a loud clicking-thundering wheel. Like a branded Logitech feature with the possibility of smooth scrolling and blablabla, which in reality is absolutely not needed, it all just causes inconvenience - "stand" under the thumb. Also not needed, it interferes with precise positioning of the mouse and rubs the finger itself. The left should always be a flat, relatively vertical surface. At least in my opinion - huge dust collectors