I have 2 c17's and a b17 and prefer the C17's altho I like the B17 too. I can do 100+ mile rides and never once think about the seat. my longest ride is 111 miles and seriously never once thought about the seat, zero perineum discomfort, I have done many 80mile + rides this year on the C17's one is a C17 special which is slightly different than the regular C17 but both are nice for longer rides. mine are set perfectly level.