This chair fits me pretty well. I'm 6'2" and about 200 lb and I have a little room left for the width of the seat and plenty of room to the arm rests. The head rest doesn't go high enough to be very useful unless I am leaning back (my shoulder hit the bottom of the headrest if I sit up straight) but I rarely sit back while working so for me it's a minor issue. It rolls well and adjusts total height arm height lumbar support height and headrest height as needed.
This chair is really comfortable for long hours of sitting. It truly does support your back and your butt without aching. Also the installation was not hard at all.
I am very pleased with this task chair. Due to the Pandemic I've been working at home for about 9 months and just recently decided to upgrade my "work" chair. It is like night and day. The support this chair gives is incredible. Definitely would recommend it. It was easy to assemble and went together like a breeze.