Neither are rare, but they are the top of the line for Bally's "Magic Screen" games. I've owned both and still have the Silver Sails. I think they are identical except for the artwork.

I kept the Silver Sails because i love the artwork, especially the playfield art and coloring. The game matches with the cabinet, back glass and playfield artwork through out the machine. The Golden Gate playfield artwork always seemed out of place to me and doesn't match the game theme.

Either game is very desirable when it comes to Bingo Pinball Machines and you don't see them up sale that often and when they are for sale the sell quickly.