I have a regular riders medium (the large is the same size exactly, except for a longer nose to interfere with your boys and lay on the tank) in neoprene. Neoprene rubber costs more, lasts longer and gets a 2-yr warranty. The cheaper polyurethane only gets a 1-yr warranty.
I really liked mine and rode it in all but cold weather. It is especially good in hot weather and long rides. A corbin seat drove me to it, but after the Corbin went away, I used it on my old big boy too. Like an air mattress, proper inflation is no more than half or a bit more (and only raised me in the seat a little bit). Fully inflated you bob around. The non slip cover keeps it in place solidly (even on hard braking) and I never used tie downs. It would be easy to steal (and expensive) so it went in my bags at all stops. Since I got a brand new Bigboy, I have not used it as much, and have not been on many long rides lately. For me, it made riding all day possible with no complaints.
They are very well made. I like to stand up on the bike to stretch and to blow the hot air out of my clothes, and I once plopped down too hard and blew out a side seam. A hole can be repaired like any innertube, but a seam tear is unrepairable. The company (ROHO) is not friendly; I asked if they could fix it, they asked me to send it in. After they got it, they told me it was a week or two out of warranty so they would not fix it, then they wanted an inspection fee before they would return it. I called that BS, and told them what to with it. Good product, lousy customer service.
Gel cushions retain heat (the last thing you need in hot weather). Polymer cushions do not retain heat. I think the Airhawk is the best cushion made, but just like for seats, people have vastly different opinions and experiences.
I believe the R-cruiser is simply a redesign of their regular Medium, with a jacked up price. I would recommend a regular medium in rubber.
http://www.amazon.com/Airhawk-Medium-Cruiser-Airseat-Cushion/dp/B00A9ZCAAY/ref=sr_1_fkmr2_2?ie=UTF8&qid=1460516382&sr=8-2-fkmr2&keywords=Airhawk+Medium+Cruiser+Pad+-+14in+x+14in+%2C+Size%3A+Md