Anything you sit on for 10 hours can get uncomfortable, just 'cause your ass gets tired of being in the same spot, but I can sit on the Corbin for a 20 mile ride locally, or a 600 mile ride, and with the stock seat, or any other kind of soft, mushy seat, my butt won't last 100 miles.
The only HD seat I've sat on so far that is fairly comfortable is a Sundowner, and it's what I'd call medium firm.
Regarding the seat being taller, a lot of that has to do with the fact that it does not compress down to the seat pan like the stock seat does. Also, getting what Corbin calls a "nose job" on the seat narrows up the front portion, and IMO, does no harm whatever to the comfort of the seating portion, so doing that as a matter of practice when getting a Corbin would not be a bad idea.
But, some people just never get used to a Corbin, so if it doesn't work for you, it just doesn't. It does take several hundred miles to break it in though...