To chair itself. I am very happy with it, but it only been about 2 weeks have in use. The seating is very comfortable. It is quite on the feeling that it does my intervertebral discs good. I am no longer so tense since the chair. The backrest feels good, when I was only not so sure. There are only 2 small things that bother me. The seating surface is a little too short, there is unfortunately no longer, or can not move forward. I am quite large (about 1,97m) and my thighs sticking with straight posture front facing a good deal. The 2nd problem bothers me a little more. The chair invites constantly on carpet, whether shoes, socks or even barefoot (tried). Then I bought an antistatic floor mat. I thought the problem should be solved. Quite but I'm not going on the issue. The backrest invites to still and I have no idea why. It can also be heard always crackling, as one moves away from the seat back. I have the chair version with fabric.
However, sitting This is more important and which meets the chair very well. However I have to give one star deduction, due to the additionally required mat and the remaining problem with charging.