The build quality is good, quite comfortable. But I will not play FPS with: too big. I'm not a fan of the support for the 4th finger, I prefer to use the mouse to tighten rather than just put it down. I also regret that there is no 1 or 2 buttons on the right.
She asked still a little time to adapt, and even now, I sometimes miss me. It has 12 buttons under the thumb, not easy in the heat of the action of systematically getting the right, there sometimes has small failures that force me to take a quick glance on the position of my thumb.
Despite this, today I do not know how I could live without it as it is effective :)