I get great results from IsoAcoustic stands.
Results do depend on the floor and home construction for sure, but for me, I got a subwoofer stand to try out years ago. I crank up my system, the result was subjectively cleaner bass, but also much less resonance throughout my home. All the things that normally rattle around stopped or were reduced in amplitude by a large amount. My home was "singing along" with the music a lot less. Picture frames, lighting enclosures, windows, etc. all vibrate less or not at all anymore.
Later, I tried them under my 15" woofer enclosures and the results were even better... less smearing of the midrange, which results in better imaging and soundstaging. These 15s can rattle my house much more than my sub could and the result here was even better as far as reduced resonance in my home.
The thought that speaker cabs don't vibrate enough to transmit vibration to the floor is one of the most ridiculous things I've ever heard.
Ok, let's not be too rough on Ethan, he does give very good acoustic advice, although his universal
approach to side wall 1st reflections I will disagree with (He only agrees with absorption in that area, nothing else!).
What is wrong with Ethan's testing in my opinion is not that measurements don't matter, it's that the wrong measurement was used in this case to arrive at his conclusions. So the problem here is the testing modality.
That being said, my experience with Isoacoustics stands coincides with DaveC's results and yes, it is subjective. The type of testing to properly test isolation products from my understanding is quite expensive, in other words, you can't just use REW and see if there is a change in frequency response
In addition, I would like some psychoacoustic research thrown in. I have been tested with blindfolds listening two of the same type of speaker (it was a coax!) with height corrected and I was able to tell which one had an Isoacoustics stand and which one didn't. That being said, I would love for a testing modality to prove it so I can sleep well at night. Yes, I'm still unsure!
Another isolation method type to try is what PrimeAcoustic does with their RX7 monitor isolations (Recoil stabilizer: http://www.primacoustic.com/recoils/
). An avid DIY'er could come up with something similar like using a granite slab with foam like product on it (NoRez, PartsExpress Sonic Barrier, etc...)