Beyond the considerations on the mouse itself, you can find on Amazon or any online test (ie the grip is perfect, scrolling coasting is incredibly pleasant to use, but the change freewheel cogwheel is hard to access, the batteries wear out relatively quickly, the "search" button is not very ergonomically placed), I want to emphasize my long-term impressions.
First of all, after all this time and heavy use -between 1 and 7 am by day we are the geek or not: D-, the buttons prev / next and began to search discolor. The small drawing above is fading, and the metallic paint itself is beginning to show signs of scratching. However, no other part of the mouse (plastic shell, rubber, shoes ...) no signs of wear watch.
The batteries or rechargeable batteries in my case easily take two months, which is quite sufficient for months.
The "multitude" buttons (prev / next, zoom in and out, search, but also "click on the side" to the right and left of the wheel), all configurable dedicated utility in OS X (and Windows but I stick to what I know), allow an extreme freedom in the actions. For example, I assigned a Cmd + W wheel to the right and a left Cmd + R wheel, which allows you to navigate around without lifting the mouse hand.
And she's pretty. What you ask for? :)