I had a PS Audio PPP. It helped, but the improvement was relatively subtle, especially compared to the Equitech.
The Equitech is orders of magnitude more effective IMO.
Most of the noise in your AC power is not coming from your wall circuit. It is reactive current emanating from the power supplies of all the gear you have connected. The regenerators do nothing about this source of noise.
With balanced power that noise cancels itself out; a really elegant solution.
And the SQ difference is not subtle at all, more like freaking amazing. Proper respect to Martin Glasband for figuring it out! Now virtually all the important audio video production companies use his technology. Which may be why it is hard to get one of his consumer units, they are so busy producing their larger installations.