I have. I didn't find one particularly more effective than the other. I have replaced both with albeit more expensive Neodio Origine B2s under my 3 integrated amps and a DAC in my 2nd system. I have found with the B2s the SQ has a richer tone with more body and resolution , I use 3 B2s under each respective component. I still use a set of VooDoo's under my preamp as it is as large as the shelf it sits on and the placement of the B2s require a small portion to sit just beyond the component cabinet.
Below is a link to a review by Roy Gregory. I will say that the review is largely focused on using them on top of components, I tried them that way and did not find the results he postulates with them in that manner , though Stephane of Neodio also uses them at shows in the manner that Roy did in his review. Anyway, I find them worth the price as isolation devices.
If you are in the US and find that you might have an interest reach out to Colin King at Gestalt Audio in Nashville .
