Bebop would like to think that bebop's designs are based on a thorough understanding of biomechanics and basic design principles. Here are a few of the concepts they think are important. So the lower the stack height, the better. Bebop's 11mm stack height is among the lowest for all road pedals, and significantly lower (by nearly 1-2 inch) than virtually all spd-type pedal systems
Systems with strong spring centering isnt real float. By pushing your foot back to the manufacturers idea of your neutral position, pedals like the Time road pedal are a problem if your natural neutral position is not Times neutral position. Free float allows your body to decide what position is best. If your knees are perfect, five or six degrees may be enough. The rest of us need more, so Bebops have 15 degrees. One other cool thing about Bebops is that you can twist past the release point when you think you might need to dab, and just twist back in when you clear that section - no need to pop out and re-enter from behind like with the other guys.