I really enjoyed getting to audition it in a system with which I am very familiar (and insanely jealous of!). I had heard it at RMAF and thought it was very promising but wasn't sure if I was being bamboozled in a foreign environment on a foreign system.
At Rim's, I did not notice any obvious improvement on my mono vinyl copy of Dylan's "Queen Jane Approximately". But on Miles Davis's "So What" (cd) which I am very familiar with, the improvement was marked. I don't think it was simply the difference between bypass and inserted. This recording has never sounded so vivid, spacious, and alive as it did with qol. It definitely eliminated a veil and brought out subtle colors in the music.
I had a similar reaction to its affect on surface noise. Since I listen to vinyl LP's more than 50% of the time, this could be a problem.
My conclusion is that the qol can improve the sound of digital sources with room for improvement. I don't think really well-recorded music (e.g. Chesky or Reference Recordings) with good spatial information would benefit greatly. I do think it could provide good to great improvement on most commercially available cd's. The question for me is would I want a device that I could enjoy say 25% of the time?
A good time was had by all. Thanks Rim!