I have tried a couple of CD treatments, using duplicate CDs to test effectiveness, and Auric Illuminator is my choice. First let me say I am very reluctant to apply any treatment to my CDs, if you have been around for long enough you know the history of "great" tweaks, some irreversable, that turned out to be BS, and may actually degrade sound. I don't use AI on all CDs, although it is cheap, but about 1/2 of my rock/alt CDs have treatment......main benefit is to reduce digital grain/hardness, smoother sweeter sound with no detail loss......it will not work miracles, but it is worthwhile, and can be removed with some effort if needed......I also use Bedini II on all CDs before playing, regards Sam