I started to scan that article but stopped when I came across this bit:
"Another great benefit of M/S miking is that it provides true mono compatibility. Since the two Side channels cancel each other out when you switch the mix to mono, only the center Mid channel remains, giving you a perfect monaural signal. And since the Side channels also contain much of the room ambience, collapsing the mix to mono eliminates that sound, resulting in a more direct mix with increased clarity."
I'm going to possibly say more than I know, but this doesn't seem exactly correct. They don't "cancel each other out" any more than two separate mics on the same guitar amp panned left and right would cancel each other out. Only the material that is completely identical (and now opposite polarity after the S/fig8 mic track is dup'd and one inverted) is removed by that collapse. (N.B. It will sound a lot different on speakers than headphones, where the cancellation of the opposite polarity material is not going to happen!) And, that ambience that's been recorded, i.e., anything that's recorded by the Figure 8 mic that's has a different waveform is going to remain. You can even still boost it in the mix the same way you would have widened the stereo mix.
The mono compatibility is an important factor, because it does mean that the center mic is effectively the only mic track that will contain sound that reached all mics from a centered source, and I *think* some of the comb-filtering issues that might be present in other stereo techniques are reduced, but that's a WAG.
[Pure editorial] I still think this technique is best where you do want to capture and control the room content separately from the main source. So, in some ways, it might work in both great and poorer locations, but in something like my little room, which toggles between fairly dead to made useless by external noise, I've not been able to get any mileage out of it.