i've used clips and straps, SPDs and Time's and the SPDs were my least favorite becuase (in my experience) if the cleats aren't in really good shape and pedal tension isn't cranked hard, i had more than a couple accidental unclips, whereas with my Time ATACS, regardless of how old my cleats are, have never accidentally disengaged. -i understand the desire to keep the same pedal system, but if you're riding breakless i wouldn't recommend SPDs