For a chair retailer, I am the nightmare customer. I recently sustained a trimaleolar fracture and this has severely impacted my ability to place my feet flat on the floor and affected my lower vertebrae. I approached Salli with little hope of sitting comfortably to do work as conventional ergonomic chairs had failed me; even Herman Miller chairs - I was a challenging case. As you can deduce, I was skeptical the chair would help, but I had to try all options; I needed to find a way to sit sustainably for a normal work day. After researching the chair, I made contact with David, who went out of his way to visit me so that I could experience the chair; and you do need to experience it, it has a different feel to other chairs. Due to this level of customer service, I purchased the chair and initially it seemed to make things worse, yet I was encouraged to keep going to get through the adjustment period - I had a chair on standby which I used during this process. So two months went by, and I was convinced that this chair was going to be like the rest, and just contribute to worsening my condition - then one day it happened... I couldn't stand the other chair, the discomfort from sitting extended periods was disappearing, my body had become attuned to the chair - the other chair became unusable and a source of pain. Hence, the Salli Swayfit has allowed me to be productive again in a sustainable way that fosters the well-being of my body; I even sleep better as a result of better posture during the day. So, I am writing this review as it may benefit people like myself with complex injuries, as reviews that address these issues are rare. If you have a complex back problem, this chair may help you. Give it a try, and most importantly be patient with it in the beginning - have another chair on standby if you need it during the adjustment phase. It took me 8-10 weeks to adjust, but now I detest 'ergonomic' chairs when I have to sit on them, as I know they are just contributing to postural issues and chronic pain. The top line: buy a Salli chair; invest in yourself, invest in a healthy body.