Used SPD's on mountain and touring bikes for 5 years. Picked up SPD-SL's this year and not noticed a huge difference. I never had a big problem with hot spots using spd's, but I definitely not had that issue with the SPD-SL's That said, I also changed shoes, so it's hard to say. I find the spd's easier to clip into for some reason. I ride hard and do some recreational time trials with a group, but I'm not a racer by any means either, so take it with a grain of salt.