I would disagree. I believe your motor is much more efficient when clipped in. Don't ask me to explain the math- I'm a Psychology major- but my experience tells me so. I was originally set up like you- clipless on the road, flat pedal on the hybrid- and upon changing my hybrid over to clipless I've gotten faster and stronger on the hybrid, with no noticeable fatigue difference. Besides, fatigue is good... means you're doing something right.

No, I did not spend the night at a Holiday Inn Express last night.