Probably the most in-depth comparison/discussion would be:
The biggest upgrades to help the Pro in cutting aluminum would be the HDZ:
and the VFD Spindle Kit:
The Nomad 3 isn’t a toy — it’s a serious tool, and folks have made some serious parts w/ it:
That said, it’s more of a desktop in an office space machine than the workbench in your shop/garage Shapeoko line.
What sort of parts do you envision making? What size? Out of which aluminum alloy? How rapidly do you need to turn them out and what surface finish do you need?