I used an airhawk seat pad this summer when I did 4 days of 700 miles/day on a quick scoot down to the four corners area in S. CO. I also have a Sergent seat. The sergent seat was perhaps 20% better than stock and extended my non-painful riding time by about an hour. The airhawk was a huge improvement and infinately better for crazy long days, especially if they are back to back days. You have to experiment with the amount of air in the pad. Too much air and they really roll around and raise you up. When inflated properly, your sit bone just touch the seat, and the increase in height and rolling around is pretty minimal.
They are not for "spirited riding", but for iron butt rides where you simply want the comfort. From a comfort standpoint, it is the best $1xx I have spent.