I played with my Nippon Kogaku 50mm f1.4 today and here's a little review.
It's wonderfully built and feels like it'll outlast mankind. To me everything works the wrong way and it always catches me out every time but I'm sure Nikon users will be fine.
There's pretty epic vignetting at f1.4 but it's within the range of CS5 to correct and lessons at f2 and again at f2.8 and by f4 it's gone.
At f1.4 it lacks contrast and is just about overwhelmed by all the extreme funkiness you might expect from an old funky lens at f1.4 but it could well be ok depending on the scene and lighting, just don't expect miracles or look too closely. Things improve slightly at f2 and at f2.8 it's pretty good. Ditto the bokeh. I think it's acceptably sharp at f1.4 in the central area for people pictures but the corners can look messy. I have few complaints at f2.8 and from then on it's fine. There are newer and better old f1.4's but it still has its charms, mainly the build and handling.
Anyway, when I came in Mrs WW was making me a smoothy
It was lovely
I think I prefer the earlier 50mm f2. It's smaller and lighter but of the same build quality.