When I was getting my Seat Concepts seat installed locally ($10 for a professional upholsterer with the spray glue, staple guns, etc and experience - such a bargain), he mentioned that the ultimate ass-comfort is to have the seating area routed out and a gel insert installed. Says he has done that a few times for some of the iron butt guys. Wasn't trying to sell me on it; in fact, he said he was impressed with the Seat Concept product after some of the aftermarket stuff that has gone through his hands over the years. Just mentioned it in passing - along with the fact the downside is that it is pretty pricey, about $100 for the gel insert if I remember correctly.
But really, what is a happy ass worth? I know dry feet are worth a lot, to the point I never flinch when I need to buy a new pair of gor-tex socks.
Anyways, I am generally happy with the Seat Concepts, although I don't know if I'm finding the low seat noticeably lower, and I sometimes wonder if I actually got "firm" foam instead of "standard" foam - my ass is still unhappy, but now it takes four or five hours instead of two hours, and the discomfort is much less. So I consider the Seat Concepts a successful group buy for myself as well as the others who have commented favourably.
Saw this over on TT today though - reminded me of the gel seat concept the upholsterer was talking about while installing my Seat Concepts
http://www.wr-products.com/dirt/categories/listProducts.php?category=77
Doesn't look like it is available for the WRR/X yet, but presumably just a matter of time? It will make an interesting alternative for those looking over the aftermarket seat offerings.