I would recommend the 28-85 zoom. While it is rather slow and heavy, I was always surprised by its performance. The only other Zeiss lens I used was the 45 2.8 pancake (I am not including the Contax G lenses). The rest of the lenses I used with the Contax slrs were tamron sp and yashica ml lenses.
A friend has a 100 f2 he likes very much. The same friend had the 100-300 zoom. That one he didn't like at all.