About the new forum UI, about the Emoji menu, heres a screen shot of how it comes up for me - is a bit difficult to close, have to use top right corner of the close button as when I hover the mouse over there, the last Emoji tab highlights and blocks the lower half off... not sure if this is Chrome for MacOS issue, or everyone will see it like this?
Again, is not an issue, but I imagine the forum UI devs would like to know about it! 
Cheers!
Andy
What speeds were you printing those cubes at? I assume that the STL's ARE cubes, so in theory the z steps might actually not be off, as they seem pretty, um, cubic?
If you are printing reasonably slowly, I see varios other issues - it would be good to know if the printer BEFORE the change to Duet had similar issues or if you have some example prints:
if the temp really was 190ºC, then the first layer did not have good adhesion (corners pulled up) - what does the bottom look like? what are you using on the bed to help adhesion? the heater resistance is correctly and firmly held in place? the same goes for the thermistor, almost even more important, as if it is not getting all the heat from the heater, the heater will have to get hotter before the thermistor reaches the target temp.
the layers seem more out of jink in the left cube, the corners are worse, and the color is not as "matte" - it was printed faster and hotter? in general does the printer shake a lot and make "shaky" noises? lack of repeatability from one layer to the next can indicate loose hardware or belts..
we have to try and eliminate hardware issues before isolating software problems...
cheers!
Andy