I'm going to have to agree with Grant Peterson. I have good pedaling technique, and I've tried a lot of pedals, and I agree that the primary virtue of any pedal is keeping your feet from slipping off. In my opinion, basic platform pedals are the least efficient by far- but only because they don't do a very good job of keeping your feet on the pedals. Clips with straps are more efficient, but they're such a total pain in the ass that they're not worth it. Clipless are much better, but the performance is vastly exaggerated. The only advantage in my opinion is on hills, and even then it's not huge, and if you have to deal with a lot of stops, clipless are also a pain in the ass. My choice is Grant Peterson's: platforms with pins. You can wear any shoes you want, your feet never slip off, and your performance is very nearly that of clipless, say 90-95% If you're racing, that 10% performance difference is crucial; if you're commuting, the small performance advantage probably isn't worth the inconvenience.