I pondered this question on my ride to work today.
The bottom line is; so much depends on what you expect to get out of your pedal attachment device. I think we all agree, to some point, that being attached to the pedal is a good thing, or we would not be having this discussion. If performance is not a huge issue, or you can't/won't change shoes for a ride, then Power Straps are probably fine. In my opinion, toe clips and straps are the worst option.
My point of view is biased toward perfomance. No, I'm not the fastest guy on the block. There are old ladies on mountain bikes that could probably clean my clock. Still, I push myself to improve; even my commuting rides are treated as such. Why? Because on the weekends, I enjoy group rides and going with the faster boys and girls. The harder I push myself during the week, the easier and more fun it is on the weekends. This, however, is my point of view and I only mention it so you know my point of reference.
I have never tried power straps, but if they are anything akin to the rubber straps on the exercise bikes at the gym, here's my take on them: To be effective, the straps have to be set at an angle, such that you put your foot in at an angle and when you straighten your foot, the strap tightens down against your foot. To exit the pedal, you rotate your ankle to loosen the strap, then extract your foot. I have to say that the ankle movement, in this case, is very similar to that of a "clipless" pedal system. The main difference that I see is the resistance to the cleat exiting the pedal due to the spring resistance, which, as others have said, is adjustable. Also, I have found that the straps are quite acceptable for pulling straight back against, but are of dubious value when pulling through the dead spot, an action very similar to wiping your feet on the rug. In this instance, you have to resist pulling your foot out of the straps. This would be very tiring on a real road ride, to my way of thinking.
Toe clips and straps, believe it, or not, are almost useless without the proper shoes. Done right, toe clips require a cycling shoe, not a lot unlike modern cycling shoes, except that they had a cleat that was nailed onto the sole. This cleat sat down into the recess of the pedal, then the rider would cinch the strap down so the shoe would not come out. When you rolled up to a stop, you had to reach down and loosen the strap so you could get the cleat up and out of the pedal. Newer pedals have teeth on the pedals that will grip into whatever shoes you are riding, but still, to be effective, you have to tighten down the strap so you can spin, then loosen it so you can take your foot out. However, if you are not spinning, only pushing/pulling, then toe clips run loose enough to get in and out of should be fine. I've still seen people fall with toe clips and in fact, one of the few falls I've had was with toe clips.
Again, if performace is not an issue, any of the pedal systems will work for you. If you are now, or ever plan to be interested in performance, or really and truly spinning, modern clipless pedals are the most effective answer. Just like a Cruzbike, there is a learning curve, but it is soooooo worth it.
Mark
