Wow...so, lots of Science here. But, like RayDunzi, I've been fortunate enough to compare my 'old tech' beamy system to M2s, so I'll throw in my observations.
In the listening position (also different rooms, mine is much larger than the M2s were in), there wasn't
that much difference (yes, the M2s were spectacular wrt HF).
But what really 'got me' was that in the M2 setup, I could move around on the listening couch, or indeed around the room, and 'image' remained largely the same -
amazing!!
Definitely a big move up from the 'head in the vice & it's GREAT' experience with my system.
So. Why don't I have M2s now? Cost.
If I were starting from new, and had the budget, I'd definitely go for a well designed, smoothly imaging system, especially if you share a couch with others, and move around a bit.
Experts - carry on.