This probably isn't exactly what you're looking for, but I had a pretty nice/expensive leather office chair for years and semi-recently (maybe ~2 years ago) ditched it for a $20 fitness ball and couldn't be happier. I was having some issues with lower back pain in addition to some circulation issues in my legs, and these issues persisted over several different office chairs that I tried out, and they cleared up immediately once I started using the ball instead. While you can't really fall asleep on it, I have found that I get less sore sitting on it than in a leather chair and it stores comfortably under my desk, which is a nice bonus. I don't really see myself ever switching back. For reference, I spend maybe 12-14 hours at my desk each day (I work from home and then use the same desk for non-work stuff) and have never had an issue with comfort with my exercise ball.