3 bolt cleats vs. 2 bolt cleats
3 bolt cleats are much bigger. They are better for riding because you have a much larger surface area connecting your foot to the cleat. Off the bike - not so good. They make you walk like a duck.
2 bolt cleats are recessed into the sole of your cycling shoe. You lose a little bit of the benefit while on the bike but they allow you to walk normally.
The racer types all use 3 bolt cleats. The people who I ride with all use 2 bolt cleats.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.