That 75mm is sharper than my dear wife's tongue; just got my new M1 and can't wait to save up and hang the 75 on it.... sounds and looks like the mark II is a winner.
On the Olympus site they have refurbed 75mm for $559.00
Great detail; better with a smaller aperture probably. In a high wind try hanging something heavy below the tripod head.
Remember that diffraction starts to reduce sharpness and definition on Micro 4/3 at around f/6.3... Also, DOF is two stops deeper for the same angle of view, compared with FF.
Best aperture on both of my f/2.8 Panasonic zooms is f/4, but they are perfectly fine from f/2.8 to f/6.3. The f/1.2 Leica primes (12 and 42.5mm) are best around f/2 to f/2.8!