So, I’m concluding that the M3 ceilings best fit where aesthetics are of overriding importance (no surprise there).

Best used for background music in rooms like your dinning room where you don’t want a sound stage (wonder if QSx’s would work better sound wise, as a background speaker, with a more even fill in some rooms)

Or as an effect speaker where the aesthetics of QSx, M3, or M3 on-walls don’t work (all the talk about dispersion, directivity, transparency and fixed placement make the latter better options)