I got burned with the exchange fees and charges using my Discover card outside the US. When I made a comment on RV.NET, several people suggested Capital One and I had my Cap-1 card within a few days. No fees or charges and the exchange rate is very close to what is posted on the internet. I also us a debit card from my local bank to raid the ATMs in Mexico. Each time I agree to pay X number of pesos for the transaction, but my bank refunds the charge. It is a small local bank and also gives an exchange rate very close to what's posted.
Paul