While shopping for Meadowlark speakers a couple of years ago at a dealership in San Jose, CA, the dealer had just gotten one of these and wanted to demonstrate for me the audible "improvement." My wife was with me too. We listened to a recent release of a Verve recording of Duke Ellington doing blues and then he performed the procedure on this disc while I watched the process and the painting of the inner and outer edges with the pen. Then upon re-listen to that disc there seemed to be more detail and a wider image, both of us heard the improvement. So I had him perform this on my copy I had brought along of Miles Davis' Kind of Blue and the same improvement could be heard. Could have been neuronal re-adjustment or placebo effect.
I think the degree to which improvement will be heard is to some extent related to the actual copy of the disc one has; by that I mean that if you have one that is a bit off center or unblanced in the plane of rotation, then you will probable hear the greatest amount of improvement. It stands to reason that a properly balanced, fast rotating disc will have fewer tracking errors in the first place and not require the electronics to have to "work" so hard to correct these errors. At least that's what I think, I could be wrong. But there was audible improvement. It's not snake oil by any means, but the degree of improvement will vary disc by disc. And my wife heard it too and she's a the biggest skeptic of all when it comes to "tweaks." Still I haven't bought one yet, seems cumbersome to have to do this to all my CDs. Almost like the cleaning-my-vinyl with the VPI 16.5, do it the first time only.