You can use the C76 or C82, it is a matter of preference. They both work with Mach4. I will try to summarize the basic considerations:
- The UC300ETH may provide additional flexibility as it can also support UCCNC in addition to Mach3/4.
- It also depends on the THC you are planning on using, for a high-performance plasma, you may want to consider the WarpRunner which only runs with the Ethernet Smooth Stepper.