Yeah, I love my Power Grips but the disadvantage is that they're really annoying to adjust. The extra-large ones are too big for my feet in normal shoes, and the normal ones are too small for my feet in hiking shoes (for rain/snow).

(I have size 12 feet.)

One of the things I've figured it out is that you still need a shoe with a relatively stiff sole if you want to use foot retention and pedal with the balls of your feet. I use New Balance M565s, which work pretty well. Other running-ish shoes I've tried are too floppy.