Mike,
as most of you know, I am very cautious to recommend currently the Contax system, because Kyocera seems not to be interested in the Contax line anymore and also makes no progress at least to try to communicate whether they want to drop that brand name or not. There will be new Contax digital bodies in the future, but as you know if you offer in this competitve environment every 2 years only one body, you are basically committing suicide - or shall I say harakiri
The only reason I still stick to my Contax gear are the Zeiss lenses. I do not expect anything good anymore from Kyocera, since they disappointed us too many times in the past. After a certain time you just believe not anymore a person, once you realize he is cheating on you again and again.
So let's focus on the positive part, let's focus on Zeiss. The Zeiss 24-85 zoom with N mount is better in colour reproduction and contrast than the manual focus 28-85. The MTF charts are slightly better of the 28-85, but I could not see the difference in non-scientific real life shootings.
But the difference in lensflare reduction is with all new N-mount lenses SIGNIFICANT better compared to the manual focus counterparts.
I do not own the 85/1.4 myself. But what I heard is that the new N85/1.4 is at least as good as the old manual focus one. Lens flare is again with the N-lens better.
Most N-lenses have also a smaller minimum focus distance than their counterparts for the manual focus line. This is giving you more flexibility in using certain lenses. Look for this in our manual section, where you will find all technical data of all Zeiss lenses.
If you think about going digital you should definitely stay with Contax - or look at Sony or Olympus E-1. What many people do not realize is that the Contax N-system was made especially for the use with digital cameras. The purpose was to offer fullsize chips and all lenses are designed to deliver excellent results with fullsize chips. No 1.6x or whatsoever factor of your lens. You get true widangle and the lenses are designed to give also good performance with the more demanding fullsize-chip - also in the corners, not only in the center of the image.
In this respect, I would it compare to the Olympus E-1 efforts, which are also soleley for the digital use, except that you can use additionally film with the N-system.
The downside is the pure arrogance and ignorance of Kyocera about costumer needs (hopefully Mr. Inoue and Mr. Nakatani from Kyocera in Japan will get that posting forwarded personnally).
But it is Zeiss lenses what we want, no matter which body is behind it. So Sony would be currently the only alternative - except you want to shoot Medium Format with Rollei or Hasselblad. Sony showed with the F828, that they are also able to produce for the high-end market (look at
www.cybershotinfo.com). I am sure that the F828 is not the last body in this semi-professional segment with Zeiss lenses on it.
But there is still hope. I am sure that Zeiss does not sit and wait and prays for the intelligence of Kyocera. I would bed that they have already thought about alternative cooperations. I am also sure that Zeiss will offer in the future its costumers excellent alternatives to the current Kyocera nightmare.
So to come back to the original point, I would recommend performance wise definitely the switch to the N-System. The rest is a more political question and nobody knows what the future will bring. I would recommend to go to your dealer and test the N-System against the Canon/Nikon-System. I am sure the Canon system is better in autofocus, same counts for Nikon. But they do not use Zeiss lenses, so check the image quality of the final prints to each other before making a decision.
Also the handling is quite different with N-System and the manual focus system. The N-lenses are bigger, but not really heavier. The N-lenses do not give you the same pleasure in focussing manually as the old manual focus system give it to you. The N-focussing ring is 50% steeper than the C/Y-line, the split screen focussing circle is tiny compared to the one of the Aria or RTS III. With all this you see, that the N-system was developped for the AF purpose and less for the MF-purpose, although they achieved a very good compromise (at least better than Canon and Nikon). There simply does not exist a perfect system
Hope that helps