I came to the F6b from a Vtx1800r. I had to put an ultimate seat on the x right away. To me the F6b seat is very good but i keep getting monkey butt from the heat. Im 6'1 220 lbs and find myself standing up on the pegs to vent and stretch. Just a guess but im thinking since the factory f6b seat is waterproof it does not breathe. However of all the bikes ived had the F6b factory seat is the best. I did just buy an ultimate for the F6b from another great forum member here. Everyone is really helpfull on this fine site.