Are you talking about the platform/clip combo? I just went to my LBS and talked to him about those.. I was looking at the Shimano 646's as I liked the idea of being able to ride them with regular shoes as well... he turned me away from them because basically its a PITA to clip in with those pedals because the platform gets in the way. I haven't tried them for myself, but I took his word (hes a national champ) and ordered myself a set of the 515's for $30... wayyyyy cheaper than those 646's!