Before you give up on the Shimano pedals, have you tried relaxing the set screw that sets the tension (how firmly the cleat is held in place). I still use that design, but I backed off the tension setting so that my cleats come right out with just a little effort. I can't recall one time the cleats slipped out while I was riding and I have zero problems unclipping quickly and easily. If you decide to relax the setting, be sure to back off on both sides of the pedal. Relaxing one set screw will only relax one side of the pedal. Hope this helps.