I bolted my Sherline to a 1/2" steel 12x12 plate. The mass seemed to help things, and I put the plate on top of a piece of foam rubber on top of the bench I use. A bit of added damping at least from a noise perspective. The steel seems to have helped some.
Anything your mill rests on that an vibrate will have it's own resonant frequencies, which in turn will transfer back to the mill. A table can be fine, provided it's not a card table
I've got mine on top of a heavily braced cheap cabinet base from one of the home stores. Cabinet underneath is nice to stow things.