Yes, I was able to (belatedly) evaluate a very kindly loaned RR-77. Do I understand why it works? No. But does it have an effect? Sure does in my system. But an effect that is difficult to describe. It was a physical bodily thing almost (like a lil buzz), but it made the music more intense and present. Not sure that is the best way to describe it. But it was both noticeable and a more pleasurable effect.
It is definitely on my to-buy list, but I would recommend grabbing something like this after addressing cables and power conditioning.
Think all of that is settled in my system. But I will concentrate on a turnarm upgrade first, then pull the trigger on one of these bad boys.