As a FF proponent, and at the risk of opening the old can of worms, other than at short focal lengths, what REAL advantage does FF have in the real world? Keep in mind, folks, this camera was not designed to be a replacement for a 1-series camera.
Since the M has slower AF speed, the real advatange off FF mirrorless:
1. Be able to use 6400ISO or 12,000ish maybe
2. Compact, lighter, easy to carry around