We bought two of these. They're good quality chairs at a low price. Easy to assemble. Reasonably sturdy and we hope will have a decent lifespan. I needed to put a lumbar support cushion on mine because I need to do this with most chairs. The locking tilt mechanism is helpful I never want my chairs to tilt. One funny thing: The floor model on demo at the store had been assembled with the arms facing backwards. The layout seemed odd but workable. While assembling the chair I realized that they could go on either way. There was nothing about arm orientation in the instructions. I put my wife's arms on normally and mine the reverse way because I don't like arms to get in my way. I was going to leave the arms off entirely but decided this configuration worked well. All in all a good purchase.
I have difficulty finding a chair that does give me muscle spasms. I tried the expensive bells and whistles chairs but didn’t work for me. Decided to buy a basic cheap chair - which I did and with a pillow I can use it