#This
I would disagree about David have a lot of work to calibrate it properly.
It is different kind of approach to calibration, but not difficult at all.
Anyone can learn how to do it very properly very shortly.
But I would agree - software itself is more important then HW.
And here i would choose David (not it is HP company now).
A lot of smart options, intelligent integrated into software itself is amazing.
Einscan is not bad, but doesn't give you accuracy & flexibility as David does.
Even with entry level of SLS2.

I did some scans of auto-part parts for similar purpose like it is question here - make another part.
Depend on surface you are scanning of course, but I manage to make even models for replication with David scanner and without much post processing.