There are lots of points on both side of the debate. I resisted for several years, but once I made the switch, I've never wanted to go back. Even casual riding gets done with SPD cleats on a "mt. bike" shoe.
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A conclusion is the place where you got tired of thinking. - S. Wright
Favorite rides in the stable: Indy Fab CJ Ti - Colnago MXL - S-Works Roubaix - Habanero Team Issue - Jamis Eclipse carbon/831