I have Look Keos and I've used SPDs, too. I prefer the Keos for the larger platform and "the feel" of clipping in/out. The "speed" at which you clip in, at least in my opinion, is more a question of how adept you are at using them than the pedals themselves. It does take some degree of coordination. Even when I have trouble with it, it doesn't slow me down to the point of it being a problem.