Ive been on SPDs for almost 20 years, and would never go back to toe clips, cleats and straps. I've tried Shimano road SPDs, Speedplay, and settled on Shimano Mountain SPDs. The mountain shoes are so much easier to walk on, and the cleats last forever. I use mtn SPD cleats on road shoes too, but aren't quite as sure to engage, and walking is less secure, but they work fine for riding, as long as your road shoes have the two hole mounting. Just keep the pedal mechanisms clean and spray a little spray lube now and then. For last year's Eroica California, I had to dig out the old Campy pedals, toe clips and straps, since they are required. It was a rainy day, muddy on the dirt portions, and with mud in the cleats, I took two low (zero) speed falls on the same knee. Great ride, but the old set-up went back in the box, SPDs back on, and its all good now ... except for the sore knee.

I do "pull up" on the pedal stroke on some hills, when my legs are hurting. It seems to relieve some sore muscles, and put others to work. One day I was riding with a slightly weaker rider, and kept leaving them in the dust. I decided to only use the up stroke as an experiment and soft pedal the downward stroke. It turned out to be just as fast upward stroke only.