Agreed - the IQ of my 7.5mm/f3.5 m4/3 sample is also excellent. The price for the M43 is also very reasonable.
My distance scale is fine, although the DOF is such that the distance setting is not very sensitive.
I used to use Samyang 7.5mm/f3.5 fisheye on my m4/3 cameras, and its image quality was not decent...but excellent.
That said, I found two problems: its distant scale on the focus ring is not reliable, so it was difficult and/or tricky to use the guesstimate focusing technique. Also, the "Pixco" brand m4/3 to NEX mount adapter I purchased was not well polished. I found burrs all over the mount and they would fall on the sensor every time you attach/detatch the lens/adapter combo. You would need to polish it thoroughly on your own.
By the way, Samyang employs the stereographic projection method for all of their fisheyes, and its compression of the peripheral area of the image is the smallest of all other projection methods. I think this is the best method if you are using the fisheye as an extremely wide angle lens for the snapshots. On the other hand, it is the least suitable for the special effect of the exaggerated central area best exemplified by the venerable Nikkor OP fisheye 10mm f5.6.
