I just finished the chair assembly and so this review might change later. I am 6'2 and weigh about 300 pounds. The chair is comfortable and has good lumbar support. The reason that I submit a review now is because of my sense of wonder. It is wonderful not needing to completely raise the chair and still sit comfortably. In fact a full piston extension stopped me from being able to slide my legs under the standard height keyboard tray. However the leather covering is thin and will cut easily if I am not careful. And it is almost impossible for one person to affix the back vertical seat. (probably because of the thick padding). I needed to lie the chair on it's side and insert something below the legs and work with it that way.
I work in a environment where we sit in chairs monitoring equipment all day so we need comfy chairs. This one fits the bill. The seating part is thick and very comfy with leg support to the knees i.e. it's not short and putting pressure on the middle of the thighs. The back is very supportive and it's a very solid chair. So far we've used it daily for a year and a half and still going strong. I could write a book on trying to find a good chair for this purpose that isn't $1000 or more. Took a lot of buying and being disappointed till we found this. Now everyone fights over this chair lol. Highly recommended and we'll be buying more of em.