I think the surface the rack sits on tends to determine, at least from a logic point of view, what camp to go with. If you're on concrete then mass loaded. If you're on a suspended floor then the light & stiff route.
Then there's the intangible approach where someone may like mass loaded regardless as thick, heavy, strong objects have an allure in themselves.
Then there's the intangible approach where someone may like mass loaded regardless as thick, heavy, strong objects have an allure in themselves.