Good product
I work long days at my desk - up to 10-11 hours and my hips and back were really sore by the end of the day.  I bought this about 3 months ago and what a difference!  No more hip or back pain, even after 10 hours at the computer.  Only 4 stars because I'd like it better if it were the same size as my chair seat  and didn't move around so much.
Rating: 4 stars