Vibrapods #1 to #5 along with their cones seems fine to me. I put the higher number vibrapod under the heaviest section of equipment, typically the transformer. Also use those rubber/cork sandwich squares which seem to work well. Lastly, I use numerous Butcher Block Acoustics supports, some with cones, some with adjustable rubber feet. They are economical supports and look nice as well.
The Vibrapod website has some nice tips and tutorials on how to use them properly, including how to utilize them in a vibrapod sandwich. I just don't see the need to spend much more on these things, I'm also on a concrete slab. Turntable resting on dedicated shelf mounted to a concrete wall. No issues there.