dfk41 I’ve done both so I may be qualified to offer an opinion on the differences, which I believe are significant.
The DFs are durable workhorses but a bit of a blunt instrument. Add a top quality burr and they can produce a remarkably good espresso (exceptional) for what was (up until Timemore’s 064s) an unbeatable price. It just needs a bit more manhandling than a Niche. And whilst swapping burrs on the DFs is easy, it’s not a 90 second job like it is on the Duo especially once you add the need for burr alignment on the DFs.
In other instances of differences there’s the bellows on the DFs of course (needed) versus no bellows required on the Niche. Rethreading the collar on the DFs is challenging (for me at least) but with the Niche it’s a doddle and re-centers to the same spot every time. My DFs do not (neither the DF64s nor DF83s).
In short, the DF with upgraded burrs can produce crackerjack espresso (or filter) like a Niche but needs a bit more faff. The Niche is just a superbly sorted machine that is such a joy to use.
For me though, the big difference between a DF with upgraded burrs and a Duo is the burr carriers.
But if you’re referring only to in-the-cup, if you are using the same burrs then no, probably no discernable difference.
Personally, I didnt order the Duos for the 83mm flats (appealing though) or because its a Niche (ditto) but rather for the burr carriers. It’s pure genius for the next generation of burr swapping prosumers. Visionary. I’m not likely to use the filter burrs unfortunately but the extra burr carrier will be worth every cent of the entire second set of burrs.
