Upload & Sell: Off
My 16-85 is very sharp, but I am underwhelmed by the contrast/rendering/etc. The images just look a bit flat, boring to me (very similar to the Tammy 17-50 that I owned briefly, before returning it - underwhelmed).
Sharpness for me has become very secondary, as most decent lenses will be sharp *enough*. What makes the difference to my eye is richness of colours, contrast, rendering. This is where the Zeiss' will excel.
My 28/2.8 Ais is a major improvement over either of the zooms. Obviously it's a much more limited purpose lens, but it takes gorgeous images. Currently it's my favourite Ais. (I have the 24/2.8, 28/2.8, 16/3.5, 105/2.5, 200/4). Rich, saturated, smooth, pleasing images.
The 16-85 as mentioned is very sharp, but I never warmed up to it. I'll be selling it towards a 24-120/f4, which has it's own flaws from what I read, but renders an image much closer to Canon's L's or some of the better Ais or Zeiss lenses.
Just my personal preference.