Rejoinder:
I wanted to try out the Hologon on the M8 for color images during this last trip. This lens is slow with effective f 16 always fixed when using the graduated ND filter, and at f8 without the filter. Smearing is really a small problem when using the M8, but using ISO lower then 500 is a challenge. The exposure setting is also problematic with this lens due to the wide coverage. There are certain scenes that seem to be best suited for the Hologon, including shooting indoors with windows showing outdoors light. The lens can balance such scenes very well.
There is really no problem with the Hologon on the M9 for full frame images if I get B&W images. There is also no problem with the Hologon on a film M camera for color images or for B&W images.
Not everyone will like the images from this lens. Some (or many) will prefer using a CV 10mm or CV 15mm lenses where both lenses are highly corrected for digital sensors.
Thanks for your feedback.