To answer your second question first - the unit is sold.
The most common issues posted are that the belt system for driving the system slip. They use toothed belts that mesh with the toothed drive gears on the motors and they slip - a lot. With they do, even in the slightest way, you lose you 0,0 reference and your carving is ruined. There are a number of work a rounds posted such as using zip strips or heat shrink tubing to keep the belts fixed and tight. Not everyone has these problems but lots of people do. I did and I just got to the point where I know longer wanted to tolerate the number of failed carvings the slippages produced. As I have researched other starter/u-build/DIY CNC machines I have found that belts are avoided in favor of drive screws or direct gear drives.
Anyway, thanks for the interest and best of luck on your decision.
For anyone who reads this who is having the belt-slip issue, the answer for me was simple: I just loosened the screw to the hold-down clamp, folded the extra belt material underneath the bottom edge of the hold-down clamp and tightened the screws back down. And this was such an effective solution that I have never had them slip again. Nor have I had to readjust them.