My new-to-me 2004 GSA had a Corbin, and was missing the stock seat. I did 750 miles in that seat in a day and a half, and I have to say I have mixed feelings. My rear was usually pretty comfortable on the seat, but I didn't like how low the seat was (and I'm only 5'10") as it made my knees bend more than I liked. I'm going to get lowered pegs and see how much that helps. I also like to be able to move around on the seat and the prominent dish for the rider kept me stuck in one spot.
Since I never carry a pillion, I think I'm just going to replace it with a stock seat if I can find one. Maybe keep the Corbin around in case it grows on me more.