Power line conditioners- to use or not to use? That is the question?


If you are in the "yes use them" camp.  Which ones etc.?

If you are a "no". Why?

Right now, I use outlets I built from hospital grade outlets bought from an electrical supply house.  I plug my amp directly into house wall outlet.  In speaking with a friend he highly recommended using a power line conditioner.  Specifically a panamax mr4300.  Swears by it.  Thoughts?
polkalover
From somewhat long experience, but not with every brand, I’d say the first step is to run dedicated lines. There are many threads here on the subject.
I found that most of the conditioners I used back in the day did not improve the sound directly from the wall (with dedicated lines) but could see a situation where, for example, you are in an apartment (condo or ’flat’) and cannot do much.
I would only do a try before you buy deal, though you’ll pay more that way through retailers that permit this.
I’ve had very good luck with isolation transformers. My tone arm uses a large (1/2 HP or greater) air compressor which created a nasty snap on the lines, crossing into the audio signal. (Part of the problem was that my electrician bundled the feeds for the dedicated lines). The thing that eliminated it was an isolation transformer. (Granted, this was not connected to sound producing gear, but suppressing a electrically powered device ancillary to the system).
I’ve since moved, and had dedicated lines installed using best practices, and in addition, have a large (10kVa) isolation transformer that feeds the system subpanel. Dead quiet (I have 104db sensitivity horns and use all tube equipment).
At a minimum, I would start with the dedicated lines if you can, get some direction on best practices from some other threads or those more technically inclined with a knowledge of the Code and go from there. I’ve found that commercial electricians  often understand audiophile needs better than the garden variety electrician. You want the work to meet applicable Code at a minimum. Even with the cost of pulling a permit, not terribly expensive, particularly compared to many magic black boxes.
I tried several very good passive conditionners, from Lessloss, Acoustic Revive (1st generation), Bybee Stealth and Bybee Holographic. But the best came for me when I installed the big Torus AVR16 isolation transfo. End of the game for me.
I'm about to buy an NAD M32 with Focal Aria 936 speakers. Dealer recommended the IsoTek EVO3 Polaris 6 outlet power strip/surge protector (with 1.5m Initium power cord). Anyone have any thoughts (good or bad) on this power strip/surge protector?
I use isolation transformers from Plitron. They sell directly to the public. The hospital grade units require their own electrical boxes, and may require a specialist electrical inspection, depending on your jurisdiction. Plitron also sells stand-alone boxes, which I have not tried.

I protect everything with Plitron units (3 of them). I found that special cords or other power accessories were less important than the Plitron.

A word of caution though - when they are doing their job, they tend to growl, so it’s better to site them away from the listening room. And pay attention to grounding. I suggest having a pro install them.

There are good ones out there. The PI Audio UberBuss is great and perhaps even better, and more neutral, the Zenwave Audio version of the SurgeX.

I no longer use them though, as my power at my new(ish) place is much better. I find these conditioning devices only necessary if you need them, if that makes sense. For example, at my previous place, I could not get along without the conditioning, and the difference was really, night and day.