Albert, nice analogy with cables above. They all sounded ridiculous to me until I decided to listen for myself. As you may guess, I heard a difference with cables and tried probably 30 different cables over the last 5 years before finally finding one that made me say "I'm done."
All: FWIW, I have the HiFi Tuning Fuse as the AC fuse in my McCormack DNA-125 Platinum. It makes the sound airer, and instruments sound lighter. My considered opinion is they are very much like cables in the sense that some people will like the change they bring, while others won't. I also suspect, though I am not sure, that the level of difference they bring is system-dependent as well.
Hope everyone here has a great week ahead.
Howard