I've had Russell, Mustang, and Corbin seats on my various rides, and always come back to the Corbin.

I have a Corbin driver/passenger seat with backrest (non-heat), and did NOT buy the pillion replacement - rather I had Corbin match the stock stitching. It looks and feels great, and the cost was under $700 (purchased in 2010). I went with the Russell on my BMW, because I needed a narrow front and dished pan, which the could do, and Corbin couldn't. I didn't find the cushion to be much better than stock - same with the Mustang. I just find I have more support with the Corbin.

I also use a "Bead Rider" when it gets hot - allows better air circulation, and if I get caught in the rain - I don't have to sit in water…. JMHO.