Which rarity guides do you guys use?
When I want a game (or record, or movie, or whatever) I try to remember when the last time I saw it was, what it went for then, try to imagine if it will ever be in print again or released in a compilation, how many regions did it come out in, who currently owns the rights, etc. Then I just pick a number and offer this number to someone with the game. If I can't get the game for that amount of money or trade, I try again a year later. If this never works out, then its "rare-ish" and I give up, deciding that it must be too valuable for my pocketbook. By this logic I have decided that Saturn Bomberman isn't very rare, Astra Superstars is legitimately rare, and almost any Laseractive game that isn't Pyramid Patrol is more much more rare than either. If I can't even find a guy who owns it and will admit it, then the thing is really f*cking rare. ie: Daicon Film on LD.
In other words, I use my brain. Its not perfect, but it was, like yours, 3 billion years in the making. Its pretty bad ass. Don't sell your's short.
Rarity guides are great for dudes that own a pawn shop and just want to know how much to ask for the 1.5 million baseball cards someone just traded in. They aren't very useful or accurate to private people dealing in reasonable quantities of shit.
The biggest problem with lists like this is that the people most interested in making such lists are, in general, the sort of people who love hype. The idea of a things "worth" or "value" going up excites them. These are the people who are attracted to Turbo/PCE in the first place because they heard it was an expensive system to collect for. They want the glamour...so the last thing they are going to tell you is that such and such a game is only worth $1.
Another problem with systems like the Turbo is that the scene in the US is and always has been pretty small, it was more-or-less pre-internet, and the companies that sold the stuff weren't very transparent about it. Anyone who claims they know how many copies of such and such game exists is %99.9 talking out of his ass. All that shit is just guesswork, for the most part.