Does the Chair work? Mine does! I think the design is ingenius. The back rest is totally functional. There is no pressure on the right leg and I don't sit on half a chair. The darn thing really works. in building the chair, I made sure that the height was correct for me. I simply don't know if the "guitar chair's" one size fits all actually will fit everone, but that's somthing you can discuss with the "guitar chair folks" for more information on posture visit "The human Gutarist".
The chair is simple to make, for those that have basic wood working skills & tools. The cost is relative to the type of material you use and what you want the finished product to look like. Because I intend on using mine for performance as well as at home, I had the seat and back rest professionally covered. If you want further information on building your own, email me.