I'm about to talk myself into trying a used Corbin for when my daughter rides on back. I use a Sargent with the cowl on back for just me, and the stock seat when the daughter rides with me (she doesn't like the back of the Sargent much better than stock so it's quick to just switch seats).
Sargent can't dish the back of their Monster seats like Corbin because of the hump in the pan for the storage compartment. I was going to have Sargent redo the stocker, but it's cheaper to try a used Corbin.
If I go through with this, I'll post my opinions on a side by side comparison.