Easy print, great instructions. Only slight post print clean up, but that was due to how well I have my printer dialed in.
Everything printed fine until there's an issue with the chain links being too short. I solved it by printing 5 extra links with 1mm elongation each (just lengthen the entire thing with distortion in x direction only in Cura slicer), spread them out along the chain and it installed fine afterward.
Another small issue is that the non-bucket chain links may lift up marbles, I solved it by adding a roof over the marble entry, first with tape then later 3d printed a U shape cover.
The version I downloaded somehow turned out to be v1.0 while there's v1.1 available. Please look around and make sure you have the latest version.
Overall a fun experience to build and run, all for the price of free.
This is my third OoM marble machine. Printing as we speak, but I'm confident it will work fine, as do the others.
Looks really great haven't printed it yet though.