AC Regenerator


Does anyone who has a hi end system use a AC regenerator?
If yes, how much (%) the sound becames really better?
Worth?
Which is the best brand? 

Thanks a lot,


sacresta
Post removed 
I just received my PS Audio P12 and its just wonderful. Sinewave setting is very nice with natural details, the multiwave 6 level gives the whole presentation and vocals a nice presence. This is right out of the box with 3 hours on it, I use the Cardas Clear Beyond power cord. I am using the P12 for front end only and I am using a whopping 35 watts. This new series is the real deal and worth every penny and I've owned many over the past 15 years or so. By far the best, Denali and all the rest, though the Furman Reference 20i was really good also, in fact, I kept it for my Video system. Look inside a Furman or a PS Audio and compare it to many others, are series filters and parallel filters with very little inside to justify their prices, though the magazines really help certain manufactures year or year.   
I have a PS Audio Power Plant Premier (PPP) and it's sitting in my garage. When originally purchased it helped smoothed out my CD player and  DAC.  It functioned fine for years.  A couple years ago I retired and added four dedicated 20 amp outlet.  Later the fan in the PPP stopped cycling, running non-stop.  I disconnected it to pack it up for repairs.  Once removed, I never notice a change is my system performance. Therefore it is collecting dust.  Note: during the time I used the PPP all my front end gear changed at least once, all having better internal power components.  
I’ve been thinking of purchasing a PS audio p 1000. I have a Krell Fpb 600 and an ARC Ref 6. Also have them both on a dedicated 20 amp and using Shunyata King Cobra and HC PCs. Would the PS audio p 1000 be a work with my front ends ? Thanks to all.