OK, so I did a big loop about town. Roughly 15 - 17 miles.
For the first 3 miles I had the Airhawk fully inflated (not what is recommended). I noted immediately upon pulling out of the driveway that I felt I was sitting on top of the cushion. I noted that as I accelerated, I rocked back towards the rear of the seat as air moved around inside the cushion. Slightly disconcerting, but within a couple minutes, it was a non-issue.
With the bladder full, I noticed how tall I sat in the saddle, we'll call that almost 2 inches taller than normal. I still had no issue flat footing the beast (30 inch inseam).
After about 3 miles of "ridin' high", I pulled over the did what I was supposed to do in the first pace...
Which is to let some of the air out to let the cushion settle a bit lower. I'll say I released roughly 1/2 of the air.
Again I noticed an immediate difference - no more rocking around on the saddle.
Still comfy, though.
Back on the road, I noticed that I was also much less prone to passing the road surface jiggles along as it was when fully inflated. The cushion was indeed cushioning!
While riding I purposely looked for man hole covers to ride over - and what a dramatic difference in the comfort - virtually none of the impact reached my back side. I had no issues when carving turns, the cushion never moved and remained comfy until I hopped off the bike in the garage again.
I'll know more next week if I get some good weather for a ride.
Thus far, impressions are favorable and my butt is happy with the investment.
It's not a custom seat, but then again, it doesn't cost $400 - $500 either...
My Airhawk came with the cushion, the cover and two straps (plus patches). So far, it's money well spent. We'll see what a longer ride uncovers...
The "medium" (14x14) model fits our bikes, IIRC.