Light-Rigid vs. Mass Loaded Racks - Help

I'm very confused as to which way to go.

On one hand you have one camp of people who say Light-Rigid is the way to go. eg. Grand Prix Audio Racks and there plenty of great reviews to back up the product.

On the other hand there is another camp of people who say that Mass-Loaded racks are the way to go. eg. Silent Running Audio - Craz and there also plenty of reviews to back up that product also.

If it helps my equipment consists of all tube based gear, amps, pre-amp and cd player and the room in question has a concrete floor.

My current location prevents me from trying out any rack in the luxury of my own home, thus good advice is desperately sought from fellow audiogoners as to which way to go.

Btw, In which camp does Finite Elemente fall into or is it on the fence with feet on both sides?

Looking forward to your responses...
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.
You have hit an interesting topic. Vibration can actually be controlled by either lack of mass or high mass. The heavier the equipment... the more a mass-loaded shelf is desired. I think the real turning point is when you look outside the one shelf and rather to the whole rack structure as a whole. Mass loading will usually give the best sonics as it will solidify the entire rack. Light stands always have problems holding heavy equipment.
Be careful with low mass though... low mass rigid shelf materials can turn the shelf into a transducer.

The NXT technologies boon of 2002 with Clark transducers brought this to light ten years after we discovered it. We just happened to test low mass shelf materials against vibrations and found that low mass shelves can reproduce the vibrations audibly.

We were looking for anti-resonant, NOT resonant shelves so this was avenue was disgarded.

We chose high-mass because we could control the result.
I have a pair of SET monoblocks (20kg each). pre-amp say 8kg for main unit, 15kg for the pre's power supply and CD player at 12kg.

Any recommendations for a great rack. For the amp, I'm planning to put them on the floor using Basalt Rock slabs from Bocchino Audio -