2-650's and a 550...it's definitely nice to have multiple machines going at once. If you have a big run of one ammo type going you can always throw in a small run of something else without disturbing your setup...
Like Babaganoosh, I have both and the ultra sonic dosnt come close to the SS Tumbler. An hour in the tumbler and the brass looks new, the ultra sonic just gets used for gun parts now....