In my opinion I would stay away from the Centurion 4. Milltronics didn't make them for very long and they haven't been supported for many years. You won't be able to get much technical support in learning to run it, and next to NO support if you ever (and you will) have to troubleshoot and repair it.
There are better investments for $2200 for a beginner, just be patient and keep looking. This is a good website for smaller CNC's and hobbyist CNC's that are GREAT learning tools and you could possibly end up making some money on smaller parts to save up for when you're ready to move to some real CNC iron.
With today's market, there ARE some better used CNC machines than the one you're looking at..... unfortunately the shipping may bust your budget.