@dc42
Finally had time to do this test. But unfortunately missed the print time. But I did do a study to make sure FW wasn't limiting me someway or another. I wrote a small arduino program on my uno that measured the speed of the hotend to go from one micro-switch to another at a fixed distance. I then did the math to figure out how long in microseconds it should take. They were both very close to perfect. The rambo was more consistent with the time, but the duet was closer to my calculations.
Printing on the rambo, everything went smooth(except the brim/skirt, s3d issue). Printed on the duetWifi, its very jerky around the rounded portions of the model, same with infill. I know yellow wasn't the best color, but it's what I was currently printing, so I didn't switch it. Even then, you can clearly see the vibration marks on the black, unlike the yellow.
Here is a link to the images and Gcode. Black is duet, yellow is rambo.
https://drive.google.com/open?id=1DkNnZv4c34fAN3zWl1TuJxT3eX1P-2Tw