I am 6' and I could not use the headrest. Sitting in this chair as intended (not slouching) the headrest would be at my shoulders. The chair was comfortable even for 10 hour shifts. Only other notes are that the mounting points don't line up perfectly and there is some wobble to the arm rests
Very easy to install 2 people make it easy 1 person can be difficult. I am 275lb woman and I was a little weary buying this chair as a plus size person. I felt that this chair supports my weight very well and I feel very comfortable in it. The headrest is my favorite piece I get a lot of neck and back pain from my old chair. This new chair supports my neck and back and allows me to continue working while getting this support. I wasn't too thrilled on the price but it's better than paying $1200 for an HM chair!