Overall I'm very happy with the chair so far (have used for about a week). I was primarily looking for good lumbar support and this chair has. The lumbar support is adjustable and substantial. I'm finding that I like the mesh fabric; I don't have any sagging issues right off the bat (though I imagine it might stretch a bit in a few weeks/months/years). The only thing that wasn't great about the chair was the neck rest. I am 6' and the neck rest falls below my shoulders actually getting in the way. Taller people might want to consider not installing the neck rest. I ended up going to my local hardware store and buying a couple of brackets that allowed me to raise the headrest by a few inches. It is now in the perfect location. The adjustment didn't require any drilling or damage to the chair and cost about $5. I would definitely recommend doing that if you are wary of getting this chair because of the low neck rest.
I already have the same chair in the office and love it. Finally broke down and bought one for my home office as well. Very comfortable and has good back support.