Core One MMU, 0.25 mm nozzle and cheap ABS
Not a print problem, just a quick heads-up as there is (AFAIK) no official preset:
I simply copied single-extruder 0.25 mm settings to MMU and it worked fine in this 5h print job (for 38 grams of "payload" plus 0.6g wipe tower).
For my needs, it's a significant step-up in print quality. Most importantly, the sidewall quality is better. The wavy lines are not VFAs caused by the printer but the inner structure shining though, as the white center area needs to be anchored in the blue outer shell for robustness. For comparison, the picture shows an earlier print with the 0.4 mm nozzle (black studs). The advantage of the finer nozzle is three layers perimeter instead of two.
The top surface finish shows some "pinholes" at the corners that aren't there with 0.4 mm nozzle. For a smooth top layer, the large nozzle is better.
I start to like the "feel" of those parts. Surfaces are rough but the friction between assembled parts is just perfect. Toy store reference parts start to feel like production rejects, too loose...