I haven't used enough to pass judgements on many areas of the lens, specifically the bokeh, but so far, I think it's optically competent. Definitely no worse than most Japanese manual focus lenses in the same focal length and aperture. I like the long focus travel; it makes precise manual focus so much easier. But to me, f2 is a rather slow aperture for a 50mm lens; it's not so much as too slow but more to do with more shallow depth of field to isolate the subject.
Will update when I use it more.
Arsat H 50mm f2 on NEX-6. Taken with 5D II & EF 100mm f2.8L IS. Click for larger.
Angry Birds - Arsat H 50mm f2 & NEX-6. Click for larger.
Snickers - Arsat H 50mm f2 & NEX-6. Click for larger.
Noise Curfew - Arsat H 50mm f2 & NEX-6. Click for larger.
A Walk in snow - Arsat H 50mm f2 & NEX-6