@garebear - where are you on your search?
I recently got a pair of Townshend Podiums for my Rockport Atria speakers - directly from England, so I wanted to provide you my experience/thoughts. What the owners have said in their posts above is what I'm experiencing. My 150 lb speakers were on their original spikes w/ hats to protect my suspended wood floors.
I personally noticed a drastic improvement in sound. Crisp and detailed is how I would describe it - the boominess that used to come from the floor went away and it was a more controlled/tighter bass. To say that the bass disappears is completely false. The vocals are now dead-on coming from the center of my system. Just based on the engineering of the podiums - the fact that it's floated, I would be skeptical of other footers that just act as barrier to vibration. To me - this is the best isolation for speakers. I was also able to maneuver the speakers onto the platform by myself with the aid of two air-wedges that had the capability to lift up to 300 lbs - without those, it would have been a two person task. This was a suggestion provided by an owner who had posted a very detailed review here on A'gon.