Originally Posted by
A_Camera
If you buy something new buy an Ethernet controller, not USB. You can run both the UC400 and UC300ETH with Mach3 if that's what you prefer, or buy a UCCNC license. UCCNC is more modern than Mach3 and is very well supported. It is also very cheap compared with other alternatives. Never the less, if you want to continue using Mach3 you can just get their controller and use the free plugin for Mach3.
In any case, Ethernet is more reliable than USB, regardless which motion controller you are buying. Whatever you do, you should watch out for the eBay fake controllers.