I would just buy a phase converter from craigslist. You can normally find a good price on a 5-10 HP one around here.
If there is a user base for the EZCAM and it works for you, I'd say keep it. Does it send a program to the BOSS control and then it runs on the machine? If so I am pretty sure the BOSS control can't handle full 3D simultaneous motion. Obviously mach3 can and there are thousands of folks using mach3 and dozens using the hillbilly board with mach3, including myself.
Also it looks like Jamie Hyneman from Mythbusters there behind the mill.