I've had the Comfort Seat by Yamaha and the Corbin Gunfighter seat and, IMO, the Corbin is far superior. As Red Wazp stated, the Corbin is quite firm. When I first got mine I thought the "hardness" of the seat would be a problem. However, after the first ride, I found that it's VERY comfortable. I think the firmness actually help with fatigue. It doesn't sound like it would make sense, but that's how it works for me.
The Corbin I've got is the "carbon fiber" pattern, which most people will tell you is quite slick. I found this to be true on the first few rides on the seat, but after about 5 or 6 decently long rides (200 mile days), the slickness seems to wear off and I didn't have any problem sliding forward under hard braking. People have said that the regular leather pattern isn't nearly as slick as the "carbon fiber" pattern, so if you're ordering one from Corbin, you may want to go with that.
The Corbin does slope forward slightly, although IMO not nearly as much as the stock seat. It definitely has more of a "cup" on the portion where your butt sits. I found it to be a huge improvement over the stock seat.
I bought mine from another member on SBN who'd only used it for about 50 miles, so it was basically brand new. The point being that I haven't dealt with Corbin directly so I can't make a judgment on Corbin's customer service, although there have been enough negative comments made that I'm thinking there might be something to it.
Another thing to remember is that you can send your Corbin to them and have them modify it so it better fits you. If you got one and thought it needed to be more scooped out in the seating portion, you've got the option of sending it to them for modification.
For comparison sake, on the stock seat, I could ride for about 30 minutes before the "butt burn" became unbearable and I had to stop for a minute. On the Comfort Seat, I could go for probably an hour before it set in. By contrast, on the Corbin, I can easily ride for 2 or 3 straight hours before any sort of fatigue sets in. The difference is night and day, for me anyway.
Hope this helps!