Spd cleats are a lot easier to walk on, and unless you are Tom Boonen in a pack sprint the difference in performance probably doesn't matter. I used Look for years starting when they first came out in the 80s, and having now switched to spd, really haven't looked back. Either way, with any clipless rig you aren't going to space out on loosening the strap at a red light and fall sideways onto the road as everyone has done at some point with toe clips 
You saw me and didn't stop?
