I'm going to do some testing on my credit cards next Int'l trip to see which is best. I have visa, mc and amex. Does anyone know if it matters whether I make purchases at the same time - or can the test just be same day?
I did a test in the past for my ATM cards between Citi MC and HSBC MC (pulled out the exact same amount one right after the other) and the rates were nearly identical. Perhaps MC is always that way regardless of issuer.