I've used The Speedplay Frogs for more than 12 years for my mountain bikes. Little or no learning curve to deal with, just slide your foot forward on to the pedal starting with your heal out a bit rotating the heal in as you move your foot forward and you are in. Just move your foot laterally to get out. No noticeable resistance to either movement like the springs in SPD pedals. There is is some degree of float but not like the Speedplay X and Zero series pedals. Your heal can rotate out a bit but not in very much. Wear on cleats and walkability will depend a lot on the shoes you are using. The cleat on the bottom of the shoe is a bit lower in profile than the SPD cleat. The shoes I'm using now have a vibram sole that protects the cleat nicely. No sound at all from the cleat meeting the pavement or ground with these shoes. Previous pair of shoes didn't protect the cleat as well and I could feel the cleat hitting as I walked sometimes. I've swapped my Speedplay Zero's for the Frogs when I'm in more of a touring mode on road bikes for the walkability. I've toured with SPD cleats and pedals and they worked well, for me the Frogs are better in terms of walkability. The Frog cleats are fairly durable, I'm on my second pair in twelve years and getting ready to swap out for a third set of cleats. The pedals are on their second set of bearings and are ready for a third set as well. Hope that answers some of your questions.
Curtis