During a recent trip to the USA I used both the Marriott Rewards credit card, my American Express card and my Lloyds Bank Avois Cred card to pay hotel and restaurant bills.
The exchange rate for the Marriott Rewards credit card was on average 5 cents lower than both the other cards. I called Creation and asked them to explain and was told it was to do with the rate charged on the day the transaction was made. This is nonsense since the difference in exchange rates over the course of 20 days was the same.
Amex rates on September 12th was 1.57 to 1.60 on Sept 23rd
Lloyds rates on September 17th was 1.59 to 1.61 on September 30th
Marriott rates on September 13th was 1.54 to 1.56 on September 29th
The transaction fees also look higher than other cardsd
Best overseas credit card for UK based people is Halifax Halifax | Credit Cards | Clarity Credit Card
I only use this card for our overseas trips, it has an excellent FX rate and no charges.
It therefore provides better cash back than the other cards as each transaction is costing you less.
AMEX cards are awful to use overseas, poor FX rates and they charge transaction fees.
This is most interesting. I wonder if the terms are different for UK cardholders than for US cardholders. If course being a US cardholder, I would be happy about the 5 cents lower rates. US cardholders (Premier MR Visa) do not incur FX fees. I would hope that UK cardholders don't either. It should be clearly stated in your terms. Sorry I am of no help.