I had one Corbin seat, bought it used, found it heavy, seat pan was rough, didn't fit well, and was hard and uncomfortable though to be honest I didn't keep it long enough to bond with it.
Have had four Sargent seats, three of them worked well and stayed, one used one was a bit soft and got resold.
Of the two, I clearly recommend Sargent, though every butt is different and there are satisfied Corbin users out there.
Finding a good seat is a tough nut to crack, LOTS of seat threads on the forum, most of us have BTDT, so good luck!
Cheers, Dave