For what it's worth, I have the Corbin seat for my WR250R. I have put a couple thousands miles on it and continue to find it wayy toooo hard. And I'm not one to complain about any seat. When I press down on it with my fingers - it barely budges. I bought it because I wanted to lower the bike one extra inch beyond the stock lowering mod I had completed. One advantage with the Corbin is that it's slippery, so when you slide your leg over the seat, it slips across like butter. If the bike still feels tall - the slippery seat can make it easier to toss your leg over.
I recently installed the YamaLink, which has lowered the bike about one additional inch. As a result - I've now replaced the Corbin with the stock seat. Wow. It feels luxurious compared to the Corbin. Nice and supportive. Granted - the stock seat covering is pretty sticky - so my leg doesn't slide over the saddle as easily. Still - it feels like a big improvement. And it fits better (less of a gap) with my IMS 3.1L fuel tank, and I think it looks better too. I'm keeping it on.
If I were to buy another aftermarket seat, based on everything I've read, I would probably go for the Seat Concepts saddle. It seems to have good cushioning, yet it is wider than stock. To me - that seems to be the secret incredient. Don't spare the padding. And just make it a little wider.
My 2 cents.
Mike