Finally I had the opportunity tonight to test this lens, modified to fit on EOS 3 weeks ago but somehow I never had time to take couple of test images. Tonight, I did it just before clouds rolled in (they are even visible on part of the image as lighter background).
The standard 100% crops from 15x stack are attached below (from DSS TIFF file, image was enhanced in DPP in terms of contrast and LP removal).
15x15sec, ISO1600, @F4.
The lens is very sharp in the centre, but still mildly suffers from lateral CA at corners. For $150 (and a bit of tinkering), it is a very good deal, methinks
It is close in performance to JJJ's Tamron 90mm F2.8 (but not as good, CA is more visible on Canon - it is similar to 200mm with internal iris).
I will try to see in the next couple of evenings how it performs @F5.6, and if CA can be reduced by use of external aperture (which I expect to be the case)..