Like so much in the world of audio, YMMV. That said, these really work for my system (modified Naim amplification and Impulse Td712 single-driver speakers ... so a system with not so much bass depth, but lots of pace and drive. I already use extensive power conditioning and IMHO stupidly expensive mains cables, but even after all that these still make a very clear improvement revealing significant levels of detail, air and ambience but without adversely impacting the timing, weight and drive of the system. Recommended 😄
Just a quick update, I now have quite a number of these and used together in series in critical parts of your system (e.g. the digital clock or reclock circuits, or as near as you can get to them) they perform even better.
Add an iFi ac iPurifier or two as well and you may find as I have that performance is transformed, depending on your system and power supply.