There are many choices and a lot depends on what you want to do, what you can afford, and personal preferences!
One of my personal preferences was that it was made in the USA and that eliminated a lot of them. There are a lot of CNCs on eBay made in China and not that I questions their quality I do question their customer service. A number of new entries from Germany and Austria but I do not know where these are made or, again anything about customer service.
If you are starting out in CNC you waqnt/need a good support system!
Back to the selection of a CNC, as stated above, there are many choices:
Legacy (one of my finalists, very good customers service/reviews, made in USA)
Shopbot Tools (other models, have not had any occasion to use customer service as yet)
Laguna (good tools, bad customer service, check this site for comments)
Shark CNC (alos sold by Rockler, some very poor reviews, no word on customer service)
K2 CNC (good machines good reviews, no revies on customer service)
CAMaster (I see these mentioned on the CNC Zone)
You also need to decide on desk top versus floor, router versus spindle (and spindle voltage requirements), dust collection, additional software (depends on what is supplied).
There are the LJ on this site that use CNCs that will probably supply input too!
You can also check out sites like
CNC Zone for a lot of very good information including other manufacturers.
Or specific CNCs like
Let's Talk Shopbot