I have three of these mice in use. What I particularly like - The very small receiver on the PC, which will always remain infected even with my 2 notebooks. - The wheel, in which the grid is switched off and with which you can then very comfortable scroll through long documents or Web sites. - The mouse works on any surface.
The Application Key I have connected as double. The horizontal scroll function works very well. The side buttons could be lifted a little more.
Positive noticed me is that 2 adjacent operated mice does not interfere with each other (such as my previous use Logi mice was the case).