Belt is cleaner, looks cool. But CTPO, no power advantage. I have been involved in fourteen different A-B-A tests with Jesel belt vs quality chain and gear and the results I have seen point to the chain making a hair's width more power. Also, no difference in harmonics as measured electronically for vibration and or sonic changes.
Ed's suggestion for the Rollmaster is good. They also manufacture a chain set that allows for timing changes without removing gears.