If you look at the isolation platform that ED is offering, it bears a striking resemblance to the "Gramma" and/or "Great Gramma" that Auralex Acoustics has offered for years primarily for guitar and bass players to decouple their large amplifier speaker cabinets from the floor. Last year I bought two "Grammas", one for a front-firing Paradigm sub and a second for a down-firing Outlaw which I felt in this case would be more appropriate giving the sound a smoother surface for the woofer to distribute the bass rather than a rug. It cuts down on the vibration to the floor but |I guess that raises the question as well should the floor be an integral part of the sound coming from that speaker? One thing I did notice was that whether or not the sub was on the isolation platform, it didn't seem to affect the distribution of bass within the room.
Bottom line, did they make a difference? Really hard to say since whatever subtle differences there might be, as in much of audio, it could be something that grows on you over time that really wouldn't be noticed until you removed it. I have yet to do that.