Nice, in-depth review. I can only imagine how tricky reviewing a chair is because of how subjective they are - everyone's ass is different, after all. Personally, I don't think I could buy a chair without at least sitting on it first, but I seem to be very picky in this regard. I found a fairly basic office chair years ago and, after a while, preferred to spend twice what I paid for it to have it re-upholstered rather than buy a new one - I've been to several stores and tried numerous chairs, from basic office ones all the way to ludicrously expensive ergonomic monstrosities. None of them were good enough to replace the one I was used to and it was not manufactured any more.
In the future I would appreciate some more attention given to the wheels since they not only affect the noise but also have the potential of damaging the floor in the long run, although I have to admit, I don't have any idea how to review them. Best ones I found are the roller blade style, soft with ball bearings. The rubber coated plastic ones gather particles and start behaving like sandpaper after a few weeks. Thankfully, it's a user replaceable part in most cases.