Very nice well made comfortable chair. Good quality materials. Highly adjustable. I love the mesh seat. I removed the head rest as it seemed a little superfluous and made the chair look big in my (small) office. Instructions to put it together were fine but the allen wrench is a knuckle-buster. The components are beefy (there is nothing 'cheap' feeling about this) so the chair is a little heavy to pick up and move around once it's assembled but it rolls well for transport. Probably needs a mat on most carpet if you're going to roll around while seated though.
I really like the Hyken chair but would prefer it if the seat was adjustable seperate from the back rest. Sometimes when sitting all the way up the seat is a little too far back and would be more comfortable if it could slide forward some.
I'm 5'10" and 185 lbs and this chair was comfortable for about 3 months. Now as soon as I sit down I get burning/numbness in my legs and rear end. I sit for at least 8 hours and the only chair I've found relief with is the Aeron (well worth the money for a 12 year warranty).
This chair is comfortable and adjusts to fit well to whomever is sitting in it. We bought several for our offices. Some folks are not fans of the headrests - but those can be removed. I personally love being able to sit back now and then to rest my head. We will definitely consider purchasing more as our other chairs need replacing.