The only reason that I use SPDs is teh fact that I have a bit of neuropathy in my feet. I just can't feel where my foot is on the pedal without looking down, and I have to look down a LOT. Without clips I find I am putting my foot all over the pedals. Pushing with my heels or end of my toes causes me a lot of leg pain. I've also slipped my feet off the pedals and jammed my legs into the ground, and barked by legs up pretty badly. I use dual sided pedals, They work for me.