Okay, so the guy you're responding to is certainly trolling quite a bit, but could you please give me a link to the review? There have been dozens of reviews/tests done on the Zeiss and I can't find one that says it's "behind the Japanese" in either performance or usability.
Actually I am speaking of 2 reviews published in paper magazines Chasseur d'Image and Reponse Photo, widely believed to be 2 of the best 5 publications in Europe.
All their tests are done using DxO tools and their objectivity is unquestioned as far as I know.
- on the quality side: they loved the Zeiss 24-70f2.8 on the A700, but found it to be lacking in the corners on the A900. They write that it is an excellent lens still, but it is not best in class.
- on the usability: they are refering specifically to the fact that on both the Canon and nikon 24-70, zooming out affects the position of the inner barrel relative to the lens hood, which offers much better flare protection on the long end (70 mm). On the Zeiss, the whole lens front moves forward together with the hood that therefore ends up being very short so as to be able to cope with the wide angle position.
Unfortunately, I don't think that they have web versions of their reviews, but you can order past issues from the site www.photim.com