Ultimate makes a great seat.
I have about 5k miles on my Ultimate seat, and I love it.
Having said that, for full disclosure, I have never sat atop a Corbin for any great distance, but I can tell you with Corbin, I see a lot of Airhawks, Butt-Buffers, sheepskins, and beads (for various reasons of course). The Corbin is a much stiffer feel, and this is greatly a personal preference thing, so I will only speak to the Ultimate.
Great seat. Very comfortable, and the fit/feel is good over the road. I am 5'11", 215lbs. The mid-rider is good for me and the Mrs. If you're taller than 6', you will most likely be more comfortable (as the driver) with the tall boy, just keep in mind, the extended 2" you get as the driver, is at the expense of the passenger.
Ryde safe.