As to the electronic dosing function, I do not think there are differences between rotation based and timer based. Although it can be set to 1/9999 rotation interval, the grind efficiency is severely impacted by how many beans / pressure you add to stop popping, so the rotation based and timer based cannot as precise as weight based. I am single dosing, so I just used it as a motorized HG one.

You can add a bean hopper on it. It is compatible with Super Jolly.
You can easily remove the remaining beans by removing a screw, but there will be many beans in the dial collar just above the burrs.
IMO, the dial collar is the only defect. If I lock it not tight enough, it will spin during grind and finally locks the burrs and cannot be loosened. I have to remove and reinstall the burrs to solve. If I lock it too tight, it will be hard to loosen and change dial.