A rule that should be enforced on eBay ;

"KISS is not rare. Reconditioned KISS' are not rare. Correctly restored KISS machines are extremely rare."

Xenon may have 11,000 units but it is "rare" to see them for sale. Maybe it is not a rare title - but I've seen two Xenons and one BMX on eBay over the last 5 years. So Xenon could be rare. Certainly more rare than Centaur. I think the term "rare" should take into account either the total number of units produced - BMX is a great example, and it should also take into account the number of times that game has been listed on eBay.

Rare does not mean the game is desirable or collectible. Raven is rare, yet it is the worst game Gottlieb ever produced. Rolling Stones (Bally) is rare, yet it is a poor playing game.

"Rare" should refer to the "quantity", not "quality" of the machine. It can easily become confusing ;

"Rare Bally Spectrum" - the term "rare" is used in the correct context. The game IS rare with low production numbers. It can be worn to wood or have a peeled backglass.

"Restored KISS - Rare" - Incorrectly used. Misleading to buyers. High production numbers.