This chair is great!  Assembly was quick and easy, and I was able to learn and make adjustments within minutes to get things exactly the way I wanted them.  Here's a tip:  the chair has a tilt-and-lock system; don't bother with the locking part---instead, just tighten the knob as much as you can (awkward...I found it easiest to simply turn the chair over and crank it down that way), so that the spring tension will keep you upright, while still having the ability to lean back any time you feel like it.  Overall, I'm very happy and sorry that it took me several years and three other chair purchases to finally get it right!