The same machines exist in industry. Except they are properly called Knee Mills and Bed Mills.
I use both, I actually prefer the bed mills, but then mines CNC and the head is a very heavy but counterbalanced affair driven by ballscrews.
The Seig X3 falls into the bedmill catagory I suppose. I quite like that machine and may even buy one when finally retire my manual Bridgeport. I'm planning on replacing it with a small manual mill, and the CNC's will do the heavier work.
Wayne...