I've got the Shimano SPD's on two MTB pairs and one road pair and one hiking boots pair. The nice thing is you can buy them for $10 if you have a bunch of shoes, or often the LBS will give you a set for free. I haven't had any problems with them. But I don't know what I'm missing...
My pedals are Shimano 959's and 747's and 520's. The 520's came with my new road bike, so I left on the black plastic thingy-s that make the pedals so you can ride them with street shoes if you are trying the bike without your bike shoes. And put the 520's on my spare bike.
I really wanted to try Eggbeaters, and actually had a pair that a friend got at Interbike for cheap, but then he took them back because he wanted them on both bikes, and I never got my own set.
Nanci
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"...I'm like the cycling version of the guy in Flowers for Algernon." Mike Magnuson