[PhilBa]

FreeCAD's Path module is fairly good. It supports a number of Post Processors and allows creation of new Post Processors (or tweaks of the existing ones). Also, there seems to be fairly active development in this area. In general, with both F360 and FreeCAD, you should never have to modify the GCode to get it to work with your machine. FreeCAD gives you a lot of ways to easily adapt the Post Processor without have to resort to coding.

Any popular CAD/CAM program will support nearly all the popular machines out there.