I'd never heard of the Freidman guy, but he's doing OK and his fixes and own designs are doing pretty well. All the things though in the dozens of videos just show me the same thing, over and over again. Different tones. By mistake or design, I have no idea and I could not say any were better or worse. Depends on the song. They help or hinder. Whenever you have amps or even processors that work on the positive and the negative going aspects of a signal - some unbalance happens. Worse with harmonically rich sounds. They sound different and look different. A mangled sine wave would be considered bad, but with guitars, weird distortion is character building. With modern electronics, you have virtually infinite ways to process a signal. That's great. Choose what floats your boat. However - what they do is so complex, you cannot see how what you hear happened, and that generates magic.
Reverbs for me are correct and appropriate or horribly wrong. So few are bad, but the good ones are usually realistic, or totally manufactured. Like spring reverb recreations. They rarely sound like the real thing. Often just too good. People rave over the Abbey Road reverb rooms and the captures and simulations of it, when in reality, it's a hard walled randomly reverberant space that fitted the music. It was NOT nice sounding, it just had a character. I do lots of work in churches and the vast majority are absolutely not nice in terms of what they do to the sound. I have been in dead rehearsal rooms and heard players and singers who have instruments and voices that are stunning, and you really know a good violin when you hear one. Then you do the recording and it turns to a mush - a sort of bad wall of sound. Definition wrecked. Clarity gone. Diction flattened and the words missing. First impression is a huge, wonderful big sound, that on inspection is just a mess. Even worse, we have heated discussion about the move of two mics to a few cm apart and then argue about if it is ORTF. Lately, classical folk have started arguing about Decca Trees, when people replicate them without U49's and use 87's or 414s on omni. All the science, all the absolute facts, yet, on really close listening - you can't tell. If the recordings they put up were described as Decca Tree, they could just as well have been an X/Y pair. The photos usually prove it. A bunch of people playing or singing. You can see the two big fellas singing the low parts, or you can see there is a single lady playing the flute. You see where they are, and then in the headphones or speakers you hear what you cannot see! I've taken my headphones off sometimes and checked the L and R are on the correct ears and they are, but it's reversed. I've watched a video where a person in the audience drops something on the floor and you hear it on the wrong side. The singers were correct - spread L to R, but the audience idiot was on the wrong side. Then you realise that's a Blumlein stereo pair, so audience left and right is reversed. It's a great technique but not real. I have a Line 6 variax - if I dial on pitch shifts on certain strings, I of course hear it. That clear indication tweaking has taken place - until I re-open old recordings and what was so obvious 15 years ago, suddenly is just a guitar.
I love Dave Rat's videos where he demonstrates our often solid opinions on sound are shaky. Like the impact of cable length - when he used every length of mic cable in his huge warehouse to see what would happen. The result was pointless - I can't remember how far he went, might have been a mile? One of his favourite tricks is polarity reversal cancelling. Take a signal, split it, process one leg and then combine back. Revealing what the mixer or other device had actually done, and it is rarely wow. it's just tiny things unnoticable in a mix.
We have people on social media with speakers costing the price of a house, asking where they should put them. They bought them, plugged them in and were not blown away, so it must be a mistake, or a room fault. The audio world is becoming very, very weird.
I should say that I am a partner in a heritage lighting museum, and we are discovering now that many of the historic, famous, often collected items are actually pretty poor. We did a video recently about a great piece of kit from the 70s. What people did not know was that the main lighting came from LED, very new kit, because the old stuff just wasn't quite up to it - and while it features visually in the images, what came out of them was unpredictable. We had 8 versions of one piece of kit - consider it like the Yamaha NS10, in lighting form. We could not make even 2 of them match. To the eye, they did. The camera however revealed hot spots, strange patches, different edges to the beams. Watching the amp videos, it's clear that the same thing applies to audio products that use components that age. Quickly, like tubes or long term, like capacitors.
No point really to this post, but just things that keep floating around my brain whenever we talk of this kind of subjective stuff.