It's a lot of work, and takes a couple tries to learn a practical way of doing it with your speakers on your carpet with your back strength and patience level. The system is just a concept, you have to work at it to figure out how to apply. But it does sound very good. The benefits are intense tonal density and clear clean punchy bass. Tone becomes awesome. Flat FR through the bass is always a big improvement whether done with speaker position, absorbtion or EQ. The downside is the reduction of the illusion of image depth. There is no depth on a stereo recording, but the reflections from the front wall create the illusion of it. Ironically the strong illusion of depth is caused by room acoustic distortions, which conceal the actual acoustic space on the recording.
I have done some pseudo anechoic listening inside a totally absorptive space and it was the best sense of space I have ever heard on a recording. Of course when the music stopped my ears felt suddenly stuffed full of cotton. People scoff at anechoic listening because it is so uncomfortable to be in there when there is no sound. But a recording with natural spatial cues makes a very intense sense of space, because there is no dilution of the recorded space by local room reflections.
I am starting to think that a dead front wall and live rear wall would enable Master Set to work even better by taking the depth illusion out of the equation, and allow the recorded ambience to step forward.
But the beautiful tone, flat frequency response and the involvement make Master Set a worthwhile experiment. But get some arnica gel if you have big speakers.
I think Master Set would work even better with a special recording of acoustic bass or synth tones designed specifically for the speaker positioning ritual, if for no other reason than to avoid listening to that godawful song again. The bass notes on that song are limited in range and skip a lot of notes because the song is a simple major key. Modes could be hiding in there. Doing computer FR sweep to supplement the ears with the Master Set might be worth a try.