Well, I've used the SMP for a couple shorter rides (10-20mi) and although it is definitely more comfortable on my sit bones, it seems to be rubbing the inside of my thighs. I'll give it a little while longer. I'm also thinking my bike may be part of the problem as since my back and clavicle injuries, I have not been able to comfortably sit in the more aero position the CAAD9 requires.