I picked up a cute, cabaret Bosconian that I bring to CAX each year...even put a brand new 13" monitor in it last year as it was becoming apparent that new monitors were going the way of the dinosaurs soon

.
It's a totally underrated game, IMHO...very fun and quite challenging. And I love the rudimentary speech where the "announcer" slurs his speech and sounds a lot like Elmer Fudd ("Wed Alert! Wed Alert!")

.
I'd say there not that common mostly because most were converted to the more profitable Galaga BITD...but their value isn't that high either as most folks don't remember the game that much because it wasn't around that long...
Jon