Buying to $ invest in, or buying just to play and enjoy for a number of years, two different answers really, but to my thinking prices will be going down each n every year a little because there are more n more new titles with newer technology coming out which competes for the $9,000 plus price tag.
Since beauty is in the eye of the beholder, someone who wants that title no matter what, might happily pay alot more, but the older some games get, the more prices slowly but surely retract. Just look at every other rare title out there, everything has dropped in price due to massive numbers of different titles to compete with.
Before Australia had over 100 seafreight containers brought in from overseas in the last 36 months, everything was appreciating, but these days there are just too much to chose from, and we all know the supply versus demand rule. As an investment, most pins now are flat, but if u buy a BBB to keep forever, and you dont overpay, or if u get it for what u think is a bargain, it wont matter if its a long term keeper.
ps - a beautiful looking game which most say is a excellent player.
