At least there are some measurements to back up claims, however I question the efficacy of the product when the change with and without may be deemed by some as significant statistically, but imo marginal at -120dB. To me that says that whatever is being done is minuscule and in the realm of inaudibility. Someone with more technical expertise than me might jump in here.
Now, having said that, if they were presented to me free to try, I likely would. My guess is they would fail my Law of Efficacy. However, I have been surprised before by products or settings which had a greater influence than I expected. But, the discussion on the website and measurements are not sufficiently compelling to seek a trial. YMMV
There seems to be little controversy over plugs for unused jacks on components, so my guess is these would function similarly. I doubt we would get someone to do measurements on a comparison of simple plugs to these devices, but that could be insightful. I don't think I have seen measurements for such plugs, and my guess is they might match up with the measurements of these devices closely.
