I actually picked that mill up (unintended, just want to have a look and couldn't say no with what he had). It's your generic RF45 clone, the nice part about those mills is the dovetailed Z axis, I think the total stroke on the Z is more than the Y.
In the instance of that machine, he had (I guess I can say we have, now) all the drivers, motors, ballscrews and nuts, etc. which to me is a huge plus. The big thing I was concerned about originally was the taper of the spindle. Many of those machines are MT3 I believe, which seems stupid to me.. but that one is R8. Apparently industrial hobbies (now out of business but I believe it is now Charter Oak Automation) sells a NT30 taper spindle upgrade, just checked their website and the spindle is $325(USD).
Honestly, it really wouldn't have been a good beginner project in my opinion. The ballscrews are 2m lengths, and with the original wiring stripped off it would have taken some work just to get it back to a manual mill if you needed that to do the conversion. I don't think I would have went for it if I didn't already have the machine tools sitting to complete the project just because it would have been quite difficult to do, or I would have been trying to find someone else to either do the turning and milling or let me do those things on their machines.
I've been reading a bunch about other people's conversions to CNC, there are some really nice setups out there which gives me a lot of hope.. but you can see where a lot of people start to spend a lot more money. After it is together (hopefully it won't take too long to get running) there will be the usual upgrades waiting to happen - VFD and bigger motor, spindle bearing upgrade to get the spindle RPM up to the 8k or so range, either a TTS style tooling upgrade or a new spindle and ATC, etc.
When we get to building it I'll try and take lots of pictures of the process and the plan, and post the complete build.