Hola: after buying the same chair for myself I decided to gift the same chair to a new Rabbi and my new neighbor. A friend assembled the chair and I laid the clear chair pad (over carpet) while he positioned the chair. Our new neighbor loves the lumbar and neck support as she works from home several days a week. The chair glides over the clear plastic laid over the carpet. I'd buy for myself again and as a gift for someone else!
I did so much research and was about to shell out ~700 for a high-end chair then came to my senses and found this guy. I don't understand how some people can spend so much money on a chair. Anyway I'm 6'4" and 215 lbs and this chair fits me perfectly. My fiance who is 5'7" also finds it really comfortable. My only complaint is the plastic used to secure the backrest into the seat. The screws come a bit loose and the backrest gets a bit wobbly and I need to re-tighten the screws. Other than that this chair is great. I work a 9-5 in it 5 days a week and have 0 back problems and the chair is supportive.