I have one. It does work and cools down your body (butt). The air flows between your butt and the seat. It definitely keeps your cooler in high temperature days. I did a 26,000 trip with it.
The down side is when the temperature gets cold, your butt also gets cold. I had to cover the cool cover when the temperature was below 10 degrees. The other problem is that your sitting on hard uncompressing nylon type material. It is a rigid and can be a bit uncomfortable compare to a softer material.
I love mine and I'll get another one if I change bikes or when it wears out. It is well made and durable.