Having had the 24-70ZA, 16-35ZA and the 16-80ZA in the past, used at the time on my earlier A700 (the 16-80 and A700 were subsequently sold), I can state that the prime advantage of the 16-80 is a combination of small size/weight and excellent range on APS-C bodies. But for sheer performance, it does not, in any way shape or form, match the FF Zeiss lenses.......especially when those full-frame Zeiss lenses are deployed on a DT body.Have you tried the a33 with your ZA 24-70 yet?. And if so do you have any comments regarding differences or otherwise.
If you can tolerate the larger size, heavier weight and shorter range, and don't mind carrying those around, then there is no quesiton that the FF Zeiss lenses, which are built to do duty on the far more challenging FF environment, will have no problems in running circles around the DT lens for sheer quality.