When I saw these items on sale a while back I was tempted to get some but sceptical of their utility. So I just bought one to see what it would do on a fairly high end electrostatic headphone system (i.e. about $3K.) I plugged it into the same power strip that the audio components were in and quite liked what I heard, smoother, mellower sound, better ambience, better definition at all frequencies. And no obvious trade-offs, such as a loss of power that I have noted with other "line conditioners." When used with a Plasma tv set-up, the picture somewhat cleaner with purer colors, blacker blacks. So I ended up getting some more. My impression is that they work best plugged in closest to the components you are using although some persons suggest putting one close to a single noisy item such as a refrigerator. As a purely audio item it is really there for those with higher grade set-ups. You need some ability to resolve audio details before this type of gadget is going to be worthwhile. However its benefits with HD tv's may be more obvious and lots more people are putting large sums into tv's than audio.