I'm very happy with this chair. I love all the adjustments you can make to customize it for you. The lumbar support is great and I love the mesh fabric. Highly recommend!
The chair "tilts" your seat and lifts your feet off the ground. It makes for an odd tilt to your spine. It is not ergonomically correct and it is very uncomfortable after about 1/2 hour of sitting in it.
I am hard to please with chairs so take this with a grain of salt. The lumbar support felt like it was hitting me in the kidneys after a while and didn't give good lower lumbar support. The top edge of the chair was very hard on my shoulders if I wanted to stretch my arms up or clasp my hands behind my head. Those were my biggest problems.