I hope I am not confusing you in how I have asked my questions but I will try to clarify here a bit. I hope this helps.

I am basically looking at what clipless pedals to use to begin with. My only experience so far is what I have on my road bike. Those are the Look Keos. And I love my Sidis. Sidi makes a mountain shoe(s).

From the other threads I have read there are the two camps of what people seem to like. In the mountain clipless area there are no "large platform" clipless pedals. So I was asking why? What is the reasoning behind that?
Will the SPD or Crank brothers work on a Sidi shoe?

I have been hedging toward the SPDs although I have never used them. What is the difference between the SPDs and the Crankbrothers, or any other brand of mountain clipless?

Red Rock