My understanding is that Shimano paid Look to use the same system the Looks just have more features on them generally. I ride with the entry level SPD-SL and like them. The cost difference between them and Ultegra is outrageous for the weight savings. The only problem I had was this loud clicking sound everytime I got out of the saddle when I first got them. It took the shop a while to figure out where the sound was coming from. They just relubed them and they've been fine ever since. If you're a weight weenie or you care about them being black they're a much better value.