i have Big Guns and Millionaire totally different feel for each machine. They are both OK games.
Big Guns has the three ball multiball but with the design of the playfield and how balls are served, is not all that following and to me feels awkward. Millionaire has two ball muliball and much easier flow and feel, almost to easy maybe.
I know i used to love F14 and HS when playing in the arcades.