I have a 9 X 42, mill/drill and the 2000 sherline. I like the sherline for work that fits in the envelope and doesn't require speed. The material being milled doesn't matter as long as you take your time. The cost of the accessories is a big plus, proprietary or not. I would love to buy a cnc rotary table for my big mill for $289. As far as vibration goes, you will have to slow way down on the mill drill to be able to mill even mild steel without it.

Check the runout on the spindle if you can before taking the mill drill home.