As always, Irulan is full of great information.
My husband bought some SPD with platforms (Shimano PD-M424 SPD Pedals) that he hated, so I might as well try them. Personally, my husband did go uphill 20% faster clipped in compared to flat pedals. Unfortunately, he also fell 3 times trying to unclip. I went to the shop to loosen the tension, but my husband now hates those pedals so much that he doesn't want them anymore.
So....I am going to try clipping in going uphill and staying unclipped on top of the platforms going downhill. No way I can go downhill clipped in because of my clumsiness.
If that doesn't work, I'm going back to my Crampon Flat Pedals which weren't bad.
2014 Liv Lust
2013 Specialized Fate Expert with carbon wheelset (sold)
2012 Specialized Amira Elite
2010 Santa Cruz Juliana with R kit and Crampon pedals (sold)
2011 Specialized Ariel Sport,suspension post,Serfas Rx Women's Microfiber saddle (sold)