@Scott Mckenzie: Interference
Audio freaks will believe what they are told by marketers about overpriced sillies to make their music sound better, even when they make no difference at all. I'm sure they'd buy one of these if the prongs were gold plated.
The rest of us are more sensible and some of us even realise that this is a digital system so will be able to cope with reasonable amounts of noise on the mains without it making the slightest difference. If it gets through to your badly-designed amplifier, it will get through via its existing mains cable just as easily as by this device.
And I'm astonished that people still think that this thing is likely to put mains down their audio leads. They obviously have no understanding of electronics at all. Still, fodder for the marketers...