My first impressions are:
- Build quality is hard to judge; it is all plastic externally. Similar finish as that of the 60mm AF-S Micro Nikkor, but the Micro Nikkor feels like better quality, perhaps because it is heavier.
- The AF isn't very fast, slower than I expected. The Micro Nikkor focuses faster. However, this lens is brighter, which means less hunting in low light. My 50mm f/1.8 AF Nikkor focuses faster than this lens.
- I have mostly been shooting at F/1.4, under low light conditions. This lens is definitely more suited to night photography than the Zeiss 50mm f/1.4, which is very bad at handling point sources of light. Coma correction seems better than the Zeiss, but I can still see coma, even in the DX crop images. So much for Nikon's claim that this lens is very well corrected for sagittal coma. It may be better corrected than the older version, but I doubt it will reach the same standards as that of the Leica Summilux-M 50mm f/1.4 ASPH.
- Strong sources of light cause ghosting, due to internal reflection. These can appear as ugly purple blobs of light, floating randomly across the image. Seems to be more of an issue when the background is very dark.
- Lens does suffer from color fringing (chromatic aberration) at maximum aperture, but I suspect this can be corrected to a large degree in software.
- Overall, the lens seems usable at maximum aperture under low light conditions, which is good news. However, care is needed to avoid ghosting when strong light sources are present.