I've been suspecting this for some time, but kept saying to myself that no lens could be better than my Apo Summicron 90/2. Then I got a chance to trade an old (-76) Nikkor 135/2 with the Zeiss 100 (incl. some extra money) I loved the Nikkor which is a real vintage gem, but I get more and more confused by Nikon lenses focusing the "wrong way", and I was very curious about that Zeiss lens. Compared to the Apo it is huge and quite heavy, but the smoothness of the focusing is out of this world, and I love to be able to go stepless from street to macro. Sharper than the Apo? Hardly, but it handles strong backlight, even sun directly into the frontlens better than anything I have ever tried, and the versatility is fab!
Thanks, all of you!