I have got my Prusa Mandel I variant printing pretty well now and I am very happy with the results. It took about 5 months part time on-and-off fiddling to get the bugs worked out and tweaked to get good prints. Smooth external nozzle geometry helped but a nozzle fan made the biggest difference. The nozzle fan gets turned on after the first 4 layers. That is after a cooling fan on the electronics to keep the steppers from overheating and skipping. Then a 40mm fan on each stepper just in case except the 2 Z-axis which do not get warm.
Tree frogs to 2 different scales, a catfish and a Minecraft creeper keychain.
I still print at kind of a low speed, but it works well. Part of my initial problem in calibrating was that I did not have the extruder springs compressed enough to prevent stripping filament especially when there was nozzle restriction due to the reduced layer height on the first layer squish-out. I went to .320in measured between the washers for spring compression on my greg-wade-accessable-extruder with Ultamachine hardware kit springs. Now I get no filament stripping bits at all, that kind of stripping cause 2 jams which required tear-aparts on the hot end. But I am feeling much better now- thanks for asking.