I use Mach3 sw, and have done so since 2002, from mach2 days..

It is perfectly solid, and delivers industrial quality reliability and performance, on appropriate hw.

All "base" features will usually work on anything, be it linuxcnc, machx, or likely UCCNC.

The difficulties start to come up with advanced features, toolchangers, light bars, multiple toolposts, css, high accuracy threading etc.
Screw mapping, multiple spindles, and so on.
Multiple MPGs.