bigger is always better
but for what i seen made with the taig mill on the yahoo taig forum. i would say it can do anything you want with time
Main problem you will find with larger mill is the spindle rpm. Most will max at 5k or so. others benchmill gearhards might only do 2k. if you're lucky. atleast in the price range of a normal person :P
if you are doing pcb boards or other stuff running at 2k rpm with a 1/16 cutter on a large mill . that taig will be alot faster running at 10k rpm.