Absolutely the best money I've spent on the bike. Bought it online from Corbin.
The most striking thing to me is how much more solidly planted I feel on the bike. I think with the stock seat you're working hard to maintain your position without realizing it and you're using your whole upper body to control the bike. With the corbin, even without the backrest you're rock solid and you use your shoulders and arms for control. Makes a big difference to me.