Mini pretty much immediately upgraded with the Bondtech IFS extruder - great extruder, but won’t buy Bondtech kits again as their documentation is horrible. Mainly had the mini for flex and abrasive initially, as I didn’t want to mess with nozzle changes on the less accessible mk3s, and didn’t want to mess with flexible with the MMU. Upgraded it earlier this year to Revo hotend - had a bit trouble due to another delay with their hardened nozzles, but figured out you can get Revo nozzles from China with pretty much the same tolerances for 5 EUR each, so was just running through them until I finally got my obxidian nozzles.
Mk3s ran stock with MMU for a while, printed the TZB extruder in PC-CF earlier this year, switched to TZB-firmware, and also moved it to Revo - didn’t have much issues with MMU before that, but things are very noticeably faster now, plus even very flexible flex just works.
Not sure if I’ll upgrade it to the MK4 - the load cell setup is intriguing, but I don’t want to give up the Revo setup, so I’ll probably wait and see if mods will come up allowing me to use both.