You know how they say in real estate, "Location, location, location!" Well in collectible mugs sales the word is condition.
If your are investing your money in collectible mugs to buy and sell. Or if you are just a collector the best thing to consider is condition.
Two mugs side by side, the one with the best condition is going to sell for the higher price. This is true of most collectibles.
The exception to the rule.
You have a mug that is rare (not that many are around) and desirable (a lot of people want it). Then condition may not matter as much. But you have to know that a mug has both of these qualities before you spend your hard earned money.