There are basically two types that you want to aim for, either a Vertex or a very close clone that can have a dividing setup fitted to it, or the one like Peter's which is a little more modern and is maybe a little easier to mount into different positions, but again with the dividing setup and tailstock available.
Both of these types are relatively easy to convert to stepper motor drive (hence CNC), I don't know about the cheaper units
I lived without one for a few years, but when I did buy mine (around 25 years ago) I wondered how I ever managed without it, a lot of items that were a real PITA to produce then became easy as pie. It is like a lot of tooling, until you get to use them, you don't realise just versatile they really are. Just as an example, cutting square or however many flat sides onto a piece of bar, spline cutting etc etc. Most people just think of them as an aid to drilling holes.
Very rarely will you wear a good one out, I proved that with my stepper conversion, it works just like the day I bought it. So really, if you make the correct choice to begin with, and dig just that little bit deeper, you will have a piece of tooling that will last a lifetime, rather than a couple of years down the line after you buy a cheapo and want to upgrade it.
No-one can make that choice for you, that has to be your decision. I just made my recommendations because I have both used them and seen them in use.
Bogs