Between the zero and the mazzer/duo definitely
I’ve always found the zero more muddled/blended Vs the majors big flats they just help with the separation. Even the mrs told the difference with north star Brazilian in milk. Both times she picked the duo as the better cup. (back to back)
The mazzer Vs the duo would be harder.
Don’t forget you get used to what you are using very quickly, that’s why back to back to back testing is soooo important imo, tasting of memory is bad really.