I've been shopping for desktop CNC for our maker lab at work. Done a lot of online research.
One main question is what material will you be milling?
G10 eats bits I've read. Or are you planning on milling out sacrificial tooling from softer materials?
Aluminum milling is possible on Shopbot " desktop " machines, which appear to be most bang for the money. But your looking at 5-7k usd.
These other open source and low-cost machines seem to be fraught with glitches and various drawbacks that require many, many hours to set up/ assemble first time, and to get parts out is a bit fiddly. You have to want you tinker with machine to think it's a good purchase. One guy online who seemed pretty knowledgeable, took like 120 hrs to get his open-source kit up and running, with lots of email back and forth.