I am in a chair over ten hours a day. I tried several chairs and I always had problems with them. With this chair I no longer have these problems. Of course I get up every half hour or so and move around which is always what I have done.
This is a solidly built and very comfortable chair but just note that if you are over 6'3" tall the headrest is not quite adjustable enough to be comfortable. No matter how you adjust it kind of forces your neck forward instead of making a nice place to rest your head. That said for the price buy the chair and leave the headrest off. Its a very good deal.
I am extremely happy with this chair. I have disc issues and have had difficulty getting a comfortable chair. This one has been perfect with great support. The mesh keeps me cool in the summer and the arm and head rests are adjustable. I found it very easy to assemble.