My opinion is pretty much echoed above with one exception. If you get a printer that has a high resolution, you can prototype components if you are thinking of coming up with your own product or something completely custom. This prototype work can be done with a high resolution 3d printer for much less than it would cost to do with a cnc mill and lathe (especially when you start getting into tooling for specialized operations).
Outside of that type of prototype work however, a cnc mill with the capability to at least expand to 4 axis is far more functional for making useable parts as opposed to just proof of concept prototypes to patent and send somewhere else to produce.
--Wintermute