I just spend over an hour reading some documentation of Mach3:
https://www.machsupport.com/help-learning/product-manuals/
Partly out of curiosity what it’s capable off, partly because of this thread, but mainly because one of my brothers uses it on a bigger CNC machine then I have myself, and I may want to use that machine in the near future.
I do not get the opinion it can do much more than either GRBLhal with bCNC or LinuxCNC. Even if I could (it won’t run on Linux) I see no reason why I’d want to use it myself.
But do note I’m pretty biased.
I’d rather use flaky Open Source software, and try to help to improve it, then pay for commercial software and have a perfectly working (production) machine…
For hobby I’m perfectly happy with GRBL. If I needed a CNC machine for production instead of a hobby then I would have a hard look into LinuxCNC and it’s stability before making any decision.