I'll have one in a few weeks. My 10 has been flying since '08, so I should be able to report back soon.
To answer Mr. Froehlich's question: Weight. A 20 lb lighter prop allows carrying that much more. Important to me with two young but growing children. My battery is firewall mounted, keeping the CG in family with the stock heavy prop configuration. That in turn allows short runs of the big wires. Win, win, win.