Wow, after trying all the assembly workbenches and being stomped by how strange they work, today I found by accident your Assembly3 WB.
Finally a WB that is written with the end user in mind. I never got the other assemblies working, but with yours it was easy.
I have a long history doing CAD, including 2 years Sketchup and 4 years Fusion. Assemblies in Fusion are easy, even kinematic movement and interference detection. With your working solution for assemblies FreeCAD comes much closer to be a viable tool for CAD people like me who want to be users instead of programmers.
(Apologies to the people who made the other WB's. I am sure they do understand how they work)
I am a refugee from Fusion 360, have been using Fusion for almost 5 years now and after the latest debacle with the licensing stuff I had enough of AutoDesk.
Switched over to FreeCAD and am spreading the word.