I like Look over SPD for the more substantial platform. I have mine on the lightest tension and they clip in fairly easy but they can fall forward so it isn't that fast. I can unclip fairly quick. The cleats themselves can be slick, I switched to some with grippers and I like them better.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan