I picked up one of his products before the new year when they were being auctioned off for next to nothing - mostly just an throw away to see if they did anything at all. It does actually change the sound. It's more than noticeable in a blind A/B test. My preference for it varied greatly from song to song. At the current prices, you're probably much better off making a box the size of your components chassis out of masonite and 1x2's and filling it with quartz sand, metal shavings, or some mix of both. That would most likely also provide vibration damping in addition to EMI/RFI filtering. Essentially, yes they do something. No they're not worth the retail prices. If you don't want to put something together yourself and can find one of his products for <$40, it might very well be worth it. Greatest thing since sliced bread? No.
