I used to use looks/road cleats on my bike many years ago, but after i had my back surgery, i found that I could feel it in my lower back when clipping in/out. (its quite a twisting movement) I then got Mr Frag to put SPD road cleats/pedals and I have ridden on these happily ever since. He recently mentioned that I should maybe swap back again and give it a go (as I'm now much stronger than I was post-op), but what I want to know is what is the benefit ? is it improved power or something ? I'm a believer in 'if it ain't broke don't fix it', so wondering if its worth doing ??