After five or six hours in the saddle, it doesn't really matter how comfortable your seat may be, a little extra padding or some extra ventilation is a welcome addition to the ride. Three or four years ago I discovered the ProPad Gel Seat Pads to make my relatively firm Corbin seat a little more comfortable for Sue on a long ride.
It made two or three long days in a row just a little more comfortable for her and I have to agree, I've come to appreciate the extra padding too. One of the things I like about the pads is that they channel a little extra air which tends to keep my butt a little more comfortable in the summer and added just a little bit of cushion to my Corbin seat without making it feel too mushy.
When Sue started riding her own bike, she wanted to add a gel seat pad—which we did. Having tried several different types of pads, it wasn't until we found the ProPad that Sue stopped commenting about how hard her seat was. That was the only review that really mattered to me.
They make them for a wide variety of bikes like the Harley big twins we ride along with metric bikes and sport tourers.