After readings a few threads on the Puron, I purchased 2 on sale. One went into the wall with the Shunyata Alpha V1 power cord from my Pass 205.8. The other went into a 500W isolation transformer into which my DAC and pre are plugged. I found basically the same results as others . . . better detail, better soundstage, slightly better bass, and the instruments seemed to have more air around them and were more precisely placed in the soundstage. Confirmation bias? Who knows. But to my ears, it sounds better, and for small money.
As for those who rag on this product without trying it, I understand the jaded skepticism that many naturally have. But there are a significant number here who have them and like what they do to one's system. In this case, with a 30 day money back guarantee, put them in your system for 21 days and if you don't hear a difference, send them back. But don't say without trying them that they "don't work" or I "heard that this is what they do"