Just a few thoughts here.
1) What is your available space? Do you think you might move once or twice in the next few years? You can get good used knee mills for the same or less than those Taigs are new, however, you NEED a forklift/stacker to move them around.
2) If CNC is your objective, then go CNC. The software available now is quite easy.
3) If it comes down to money now, get a manual one with DRO (digital readout). Takes the memory issue out of machining......good for us older folks!
Here are a couple that we are looking at for our shop at work:
http://www.grizzly.com/products/Wood...wer-Feed/G9977
http://www.use-enco.com/CGI/INPDFF?P...MITEM=307-3237
I'm personally leaning toward the Enco - I hate changing belts for speed, and the square column tends to be more accurate.
4) Considered buying or better yet, building a CNC Router? This is what I am going to go with. You can do about 90% of RC stuff on a 3 axis Router. Another positive is that you can size it to your needs.
5) When comparing a used unit to new, keep in mind that tooling is extremely expensive. A used system may be worth double to triple asking price if it includes tooling and bits.