Asking which machine to get is like asking a group of car enthusiasts "which car should I buy"?
TONS of answers, and usually starts brand loyalty in-fighting. All depends on your budget, and truthfully a good stone can be cut by a good faceter on any machine.
First thing you should do is find the yahoo newsgroup United States Faceters Guild and subscribe to the digest. Lots of people there who will answer these sorts of questions almost immediately and TONS of old archives to read through.
Also there is a brand new cheap and EXTENSIVE faceting book that just came out by Tom Herbst. Shockingly cheap for what you get. Almost everything that you need to know.
Look here: http://facetingbook.com/
Buy it on Amazon--thank me later