PS Audio Power Plant 15........

horses for courses.
I believe it’s safe to say that different products and methods, perhaps especially in mains conditioning, in different locations (geographically on the grid) and in the context of a system (a whole kit in a room), offer different results more then not.
So nothing about this is simply black or white. It is a more wholistic thing then that.
One can believe whatever they would like about a particular product or product line but it’s relatively meaningless without Listening, in a context, over time to become understandable. And then, that is only one context.
I’ve literally taken the same kit to a different location and room and had to dance to a completely different tune. The nature of a perfectionist hobby.
That said, i’m sorry that the PS Audio isn’t working out for you. I have had great success with other components in their earlier product line and have yet to hear the Audioquest Niagara in a system that I understand. Conversely, I have a dear friend who’s kit sound I favor, who returned a Niagara for other solutions. Go figure.

Forgive me as I may be preaching to the choir here but have you given it time to settle in as big things like that can take a fair time. I would recommend at least a couple of hundred hours. 

I agree with jim204. Give it a week of active use so it can settle down in the system. I once purchased a conditioner that sounded quite terrible in my system for the first three days, and on the fourth day, it suddenly changed and started sounding fantastic. It was a used unit, with plenty of time on it.

Totally agree with the above.  Leave it in your system for at least a week and then switch back to the Niagara.  Then you'll know.  Then again, if regenerators were the cat's ass, why isn't everyone using them?  So your initial conclusion may well be on the money. 

For those who suggest a "settle in" period, thanks -- that's good to know. I've heard that with other things like cables, interconnects, etc. It's not clear to me where those elements are "burning in" or "settling" (as the lingo goes) vs. the other factor -- our ears getting used to a new setup. Indeed, it seems nigh impossible to disambiguate which is "us" and which is "the gear."

In a way, that's a problem, because we don't want to pay big $$ to get used to something that isn't really changing.

On the other hand, if the final experience is better, who cares? Better is better. (Of course, we're left with a question....)