What's the difference, really? Both found it really difficult to get ahead for reasons other than quality. Moore's longevity/showmanship allowed him to break through, Burley's managerial difficulties/conservatism didn't.
Probably Burley. Moore had other problems that also hampered his career progress - he was forced to retire for a year because of ulcers right when he should've been reaching his peak as a MW, and he had embarrassing losses to Eddie Booker and Burley himself that also set him back.