I had a Citibank AA Visa for several years. A few years ago, I was offered 7500 AA miles to exchange it into a Citibank AA Master Card, so I did so. Because I use it extensively, last year they waived half the annual fee and this year they waived the whole fee. I pay in full so they get no interest. MC cards are as widely accepted as Visa and the benefits are similar. If they offered me something to change back to Visa, I would probably do so, as I don't see a dime's worth of difference between MC and Visa.