Selection of suitable milling machine for CNC conversion

[magicniner]

There's a European supplier who will supply their machines already fitted with ballscrews (and I think steppers/servos), but I can't remember their name.
IIRC they were based in Austria, but it's been a few years since I looked at their website.

How do they work manually, given the question to be addressed -

Hi,
I am in the process of choosing a milling machine for hobby use.
Mainly milling aluminium, and occasional mild steel.
I intend to convert it to CNC in the future.

?