In fact, the biggest problem of this lens seems to be its price. Over $2000 for a portrait prime is really too much; you have to be really determined to buy such a piece of equipment.
solid, weather-sealed mechanical construction,, excellent image quality in the frame centre up from the maximum relative aperture,, acceptable image qualtiy on the edge of the frame,, very good correction of longitudinal chromatic aberration,, negligible lateral chromatic aberration,, lack of...
a bit too high astigmatism,, visible vignetting on full frame.