Hey Jones,
I just installed PowerGrips on my commuter bike and took them for a test ride yesterday. I rode 10 miles "before" and 10 miles "after". I'm not sure I've got them to where I like them yet (I've adjusted them twice so far) but certainly notice an increase in efficiency with them on. I have to start/stop a lot when I run errands and/or commute to work and think I'm going to be really happy with them. My husband (big feet, small toe clips) has pedal envy and I think I'll be ordering a pair of XL's for him soon.
Does this bike make my *ss look big?