I think perhaps the way the question was phrased, anybody that has not shot both lenses will not respond -- which of course limits any "lively" discussion
I have not shot the Zeiss 85, but will respond thusly:
I have owned the Canon 85/1.8, Leica 80/1.4 R lens (with Canon adapter) and the Canon 85/1.2. My fist 85 was the Canon 1.8. It was very good, but then I got a 1.2 ver I. Wow! 1.2 is really different than f1.8! Then I got the Leica 80 Lux. Gorgeous rendering, very similar to the Canon 1.2 at f1.4, weighed half as much, cost a little less, and even manual focusing was not all that bad. So I sold the 1.2.... Then I got tired of manually focusing all the time, and re-purchased the 1.8 lens -- and lived happily with that until the faster focusing ver II 85/1.2 came out. Now I have the 1.2 ver II and love it.
ALL of the above is a long way to say, if you don't mind manually focusing and no exif, then the Zeiss is certainly worth a look -- and so is the Leica R lens. However, if you want AF, then IMO the 85/1.8 is a bargain. If you plan on using the lens a LOT and want the shallow DoF, then break open the piggy bank and spring for the 85/1.2 -- after all, it really isn't all that much more than the Zeiss...
Okay, my .02 on that
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