home made CnC

I'm into scratch-built modeling, so you can imagine that a small
desktop CnC machine would be a really great tool for this hobby. I
have seen plans for sale on Ebay and other places for building your
own machine.

What I was wondering is if there is a specific machine (or plans for
one) that have been around long enough that it has proven itself to be
a reliable/easy to use design.