Craig, I would place more stock in Bjorn Rorslett's reviews than Ken Rockwell's. Whilst there are home truths in what Ken says, when you are laying down hard money it is nice to have a concrete comparison.
Bjorn, as Matt says, also rates the 1.4 highly. I think you will find it hard to find comparison between the two, especially as the
AIS isn't current (the version referred to is 1980). I think you would be happy with most Nikon 50mm that fit your cameras, they are all good, especially for the money.
Padey is the only member I know of who had the Zeiss.