I've owned both brands but must say that the Corbins fit me better. I have a Corbin Gunfighter on my '04 1200R Sportster and currently, thanks to that saddle, she is a bit more comfy for me than the much better riding '06 FJR! DFO
I've got the Sargent's and have been really happy with it. All day comfortable and no issues. I didn't like the feel of the Corbin and it slid me back a little too far (I'm 5'-9"). I've owned both Corbin and Sargent seats before and been happy with both. Never owned a Russell, but their reputation is spotless. They're just too fugly for my personal vanity factor, and I don't do a lot of cross country riding.
Another option is Rick Meyer Cycles custom saddles. I'm having one built by him right now. Some folks find them more pleasing to the eye than the Russell. Comfort supposedly on par to the Russell. I checked out a friends RMC first, then ordered one. Appears to be top quality work.
Corbin has a new seat out. They don't have a name for it but identify it as part of their 'modular seat system' which includes the smuggler, a backrest, or something they call the Ovalbac backrest. I was about to order a Sargent until I stumbled onto this new Corbin. (Now my dough has been diverted elsewhere.) The more I study the pictures the more I like it. It looks like it'll fit my butt just fine. Looks...
Someone responded back when I first posted (in the winter). He had bought the front seat but there was too much snow for a test.
We're using Bunsavers until I get my money back and can make a decision.