Im new to the audio side of things so I cannot comment on sound quality, but as a person who works with electricity for a living the power conditioning devices are not a good investment as the electronics are built to convert AC into filtered DC therefore eliminating "unclean power". Power supplies have voltage regulators to give you constant power output.
The only way that I would purchase one of these devices would be if I live on a farm with a long single overhead line that only feeds a few customers as these lines are at high risk of Lightning strikes. Even then I would much prefer to put my money into a good UPS(uninteruptible power supply) that are used commonly for PCs. But if lightning strikes close to your house nothing will really protect your gear. Your looking at voltages upwards of ~15 kV minimum.
