I don't have any comparison D2X from this scene. I will see if I have some others. I have deleted most of them. Aside from the DR, the most striking thing is the noise in the D2X file at large image size compared to the low noise of the ZD at the same image size.
Attached are a couple of files. The first is a D2X nef converted to JPG and the second a ZD converted to JPG. These are not anything special just comparison shots on a very bright high contrast day. The noise is what I was looking at.
Hope this helps some.
A bright scene will not show up as much noise as a dark one. It is when it is dark scene and I really need the extra ISO to be able to capture an image that it gets noisy.
It would be interesting to see your examples of such a scene. The information that I have from my agent is that my ZD camera has latest firmware and that image quality is same as ZD back. There is updated firmware available for the ZD camera since it is older, but not yet for the ZD back.
I had D200 before. That one was noisy indeed and shallow DR in comparison, but... with ZD I seek even higher image quality same time. I agree with your experience that the files are plain wonderful to work with from the ZD. It is possiblt to do more with them, such as +1.5 in PP and still beautiful image (given good light).