I just had a demo with a very knowledgeable product specialist. I brought a file and file, featuring RED (the new red ink is a big feature of the Z3200) from my Z3100. It was reprinted several times for comparison on the Z3200.
There was a red difference but to me not a large or critical difference. The Z3200 also has new software which allows better control of c ertain printing parameters. All in all a valuable but incremental upgrade.