Well I was able to log about 130miles on the aqua-aire cushion today. The Aqua-aire costs 39.90 US plus shipping.
The cushion is black and disappears once you plant your arse on same. Normally I can go about 30 miles before the butt bones start hurting and about 50 miles before they go numb. I just don't have any padding back there guys! Anyway I didn't start feeling any discomfort until about 100 miles and it was minor. I need to play around with the air/water mix a little to maximize comfort. I felt i had too much air in same but will let some out for next outing.
Dollar for dollar I challenge anyone to come up with a seat, cushion, whatever that does what the aqua-aire did for 39.90 US. Here is their website:
http://www.aqua-aire.com/