We’ve always loved WebBikeWorld’s great reviews, Larry Gebraski points out they have a good writeup on the Piaggio Museum with some solid advice for travelers.
(When you visit, ask how the extravagant new Massimiliano-Fuksas-designed museum that was scheduled to open in 2007 is coming along. Be sure to remind your tour guide that the museum hype came a month before Piaggio’s stock offering, then was never mentioned again.)