The Darkfield sensor actually works great on glass, wood but not on plastics, white paper, non-smooth surfaces where optical mice work. Regardless, nothing embarrassing, unless one has a desk covered with a plastic wood imitation (school office type).
The battery life is awesome! I recharge about once or twice a month while I work daily on my computer. Moreover, no need to deal with, the Logitech software informs you when the battery level of the mouse becomes critical at this time, simply plug the mouse into USB (or AC with the adapter included) and you can continue working while charging.
To recharge the battery, you have a USB cable, a USB adapter and a small area really nice pouch for storing all that (and if you often change your computer, put the Unifying dongle in).
This mouse fits snugly to the hand, which is very nice.
The Back / Forward buttons are fairly well placed and very responsive.
The Zoom button placed just below, can be programmed to what you will, personally I put it to set / remove the Mute the volume.
The dial is just great. The button to open notched move is very well placed for my taste and the notch is perfect (neither too hard nor too low).
The button under the thumb (which base, allows to change application) is rather misplaced and insensitive, so I do not use (and never click on it, even without meaning).
In terms of the coating on top, it is very solid, we see that it begins to darken slightly in clicks but no feel.
By cons on the sides, there is a type of rubber which wears slightly. On the right side, where the rubber is smooth, it has become rough when I put my fingers. And the left side, the rubber is original with small holes, it became smooth as I put my thumb. But nothing inconvenient to use, just a little less aesthetic than when it was new.
The on / off button is placed on the one hand I can turn on / off the mouse, so it's perfect.
Appraisal:
Positives: Shape Wheel décrantable, Works on glass and wood (even varnish), Glide well, Programmable buttons, battery duration, Unifying and everything else.
Negatives: A bit heavy, do not work on substrates with the laser works, wear rubbers and that's it.
Overall I would still recommend this mouse, I can find no equal for now.
