I couldn't figure out why the used Zee brake set with "known good" pads that I bought sucked so much, and were SO loud. I baked the pads, and got a week of decent (but not exceptional) power out of them, and then they got worse again. Swapped the new pads in and wiped down the rotors, and the difference was immediately apparent. Bedded them in very briefly, and went for a ride. 10 or 15 minutes of riding bedded them in the rest of the way, and wow, what a difference. FINALLY, the power I was expecting from these brakes! (Nice and quiet, too, though I haven't gotten them super hot yet.)