I have to throw in my $.02 on Speedplay LA (light Action) I decided on these 2 yrs ago based on a lot of research here and in other forums. The "light action" and "float" and double sided input as well as the light weight were the deciding factors for me. I have been very happy with them. The only problem I had was when I lost screws out of the cleat after the first year. I should have had shop install them, but I tend to DIY. On the road bike I don't have any problem with dirt.

The only other clip ins I have used are SPD. I have combo SPD/platforms on our tandem and my MTB bike. I find them harder to get into and on the MTB a little harder to get out of. It is nice that the are the standard for stationary bikes at gyms, and they are adjustable.

Can't speak to the other pedals but my buddy who has crank bro's loves 'em. He has egg beaters on his road bike and uses mtb shoes so the cleat is recess to make walking easy. YMMV.