IMHO, unless you NEED portability, i.e. you will be doing cue repair at tourneys, you are better off with a solid machine lathe. An old south bend, atlas, logan or anything of the sort can be had for under a grand.
If you want to buy new, I'd look at a Grizzly or a Jet. They seem to be the best for the dollar. You should be able to have one delivered for under $3k. Any of these metal lathes should be capable of holding tolerances to .0005 if properly calibrated and in good condition.
If you need the portability, do your homework on what you features you want, and which ones you need. The cue lathes are all capable of tip and ferrule repair, but their other functionality differs quite substantially from machine to machine. Also, remember that these light, low-powered machines are not capable of the same precision that a full metal lathe can produce.