I had a nice one about a year ago. It had a 6.5/10 backglass with flaking, 9.5/10 playfield, 8/10 cabinet. I picked it up off of cl(I think I paid $200 or something), shopped it out, and put it to auction on ebay. It went for $550.
Look out, it seems that the backglass on that one is faded! The "Delta Queen" letters are supposed to be red.
The gameplay wasn't very good in my opinion. The game seemed to punish you for hitting your shots... Those 2 standups to light 2x bonus would always deflect into a drain. The center scoop would often reject if you aimed for it. The "collect bonus" scoop in the upper left also seemed to often times kick it right between the flippers. I like difficult games, like my Gottlieb "2001" I just picked up, but this game was just frustrating, with a bland and boring art package.
Hope I helped!