That's a tough call as components can be well isolated with proper footings on many kinds of racks but from what I've read and feel, myself, wood is a very good foundation to use, especially maple.
I remember TTs skipping when walking by so it stands to reason that CDPs can be affected as well. Vibrations are just another kind of physical jitter that can be introduced and are not welcome.
The more solid the rack is, the less likely it's going to transmit vibrations to a component and when properly footed, can quickly and efficiently drain and decouple a component. That, and I feel that Timbernation stands are great to look at as well.
I guess it all boils down to what you want and what you're willing to part with.
I know they're not cheap but I've seen racks going for lots more and am not quite convinced they're doing a better job. I've also seen IKEA tables that Srajan uses over at 6moons and they seem to work as well. It all boils down to what you're willing to settle for.
Good luck in your choice.
All the best,
Nonoise