In my view, MC and Visa have about the same acceptance rate, and this is probably because the fee to the merchant is the same or nearly the same. Discover and Amex likely charge the merchant more, and therefore are less widely accepted.

My Sam's accepts MC and Discover, but not Visa or Amex. Go figure.

Also, regarding rental cars, these days it generally depends on the level of your card, not on the bank. For example, whether its a gold card, etc. Of course the programs differ from Visa to MC to Amex, and even within a program from issuing banks--for example, Citibank Visa to Bank One Visa. In my experience, its rare for a gold or above card to not include rental car coverage, and it is rare for a card below gold to include this benefit.

[This message has been edited by LemonThrower (edited 05-16-2002).]