The round coloum mills are very capable for the cash they cost but do have a few limitations, for example the head moving relative to work when the heads raised and lowered, tramming isnt easy.
on the postive its very versatile and good value.
I am currently lusting after the real small bench knee milling machines i think they look proper tasty for smaller work.
Stuart
I agree round column mills are hard to tram for a beginner. If you have to move the head in or out due to travel limitations they can be hard to re-align.