Hi Brian,
Good choices for CNC are going to be based around what you need, what you intend to do, how much money you have VS how much time you have, and whether you want to add CNC as its own hobby beside your guitar building or to have it act as a tool.
If you're getting a machine to mess around on, not to make a living, and you've got more time than money then building a kit is a good option.
If you have those things plus want CNC building as a hobby then you could build from plans.
If you value your time at more than a few dollars an hour, you won't save any money building your own unless you're a professional builder, so pick a well regarded hobbyist machine in your price range.
If you need reliability and are looking to make a business out of it, then pick a machine well regarded by people who make their living with them.
If you can be a bit more specific about your needs, hopes, dreams, wants, and budget then I can give better advice
