I have tried over the last few years, Stillpoints cones, Finite Elemente Ceraball (original), Finite Elemente Cerapuc, Cardas blocks, EquaRack MF-1 footers and HRS M3 platform.
I posted my impressions on these devices in this post:
http://forum.audiogon.com/cgi-bin/fr.pl?ddgtl&1194432236&openusid&zzIsanchez&4&5#Isanchez
All the isolation devices I've tried work well. Some better than others. So in my experience, each one of these footers or platform is an upgrade from the stock feet that came with the audio equipment.
From the isolation devices I've tried, the HRS M3 and EquaRack MF-1 footers are much more efficient at controlling vibrations and resonances than the other ones I have.
I currently have all my audio equipment on a credenza. I have the HRS M3 sitting on it supporting my turntable. I can play a silent track on the turntable and knock hard on the top of the credenza and I hear nothing on the speakers. That's how good the M3 is.
I conducted a similar experiment with solo violin music playing on my CD player. This time with the EquaRack footers. Again, I heard nothing being transfered to the audio signal.
I currently have EquaRack footers under all my equipment, except for the turntable. With these footers, everything is tighten up and I hear more of those micro details that tend to get lost in reproduced music.
I still have footers from Stillpoints and Finite Elemente. And I still use them from time to time, but just as a reminder of how good the EquaRack footers are by comparison. I also keep using the Cardas blocks: to set up the VTA of my tonearm.
I hope this helps.
Best Regards,
iSanchez