This is a bit of a myth in the business world, but there is some truth to the matter in that American Express is accepted at fewer locations than Visa and MasterCard. An unofficial survey would find that many small businesses tend to avoid this card while larger chain operations are more than happy to accept this credit card.
American Express has always has the reputation of providing both its merchants and card users with extensive benefits. This offering does not come cheaply; therefore, American Express charges a higher commission rate to vendors for accepting this form of payment.
While companies with significant volume can absorb the extra fees, many small businesses are not in a position to pay the higher rates and avoid accepting this as a form of payment.
American Express claims that it had expanded significantly in recent years and expects to continue this trend in the future. The problem for the consumer is that if they leave their home with only their AMEX, they are playing a bit of Russian roulette.
Our advice would be to either carry an alternative form of payment in case they do not accept the card, or get online or on the phone before heading out to find out if your destination store actually accepts the card.