looking at photozone (they have one reviewed for nikon) and comparing to fa35/2 or fa31 (which I know you shouldn't look cross platform but...
) the differences aren't big, considering that you lose af too. from the little I have seen (and it is only a little so correct me if I'm wrong) the zeiss lenses are ultimately sharp but dont necessarily have rendering or bokeh of some others. make me think of the 43mm limited, amazingly sharp and there are lots of beuatiful images taken with them, but sometimes the bokeh isn't so good etc.
just my uneducated thoughts
Phil