I have the Sony Visa card now run by Chase.

Also used my SkyMiles Amex.

So for my trip to Italy last month, the statements have come in.

The Sony Visa breaks out the exchange rate used and then gives a lump sum they've added on. It works out to like 2.9% above the dollar amount after the Euro x exchange rate calculation. That is, they're not adding percentage points directly to the exchange rate they use (presumably the published wholesale rate), they add 2.9-3% to the dollar amount AFTER conversion from Euros to dollars.

So for the transactions, they used 1.2733 and 1.2787 on two different dates but after the 3% they added, the actual exchange rate worked out to 1.31xx.

That seems almost as high as retail exchanges.

The Amex doesn't break it out. They give you a Euro amount and the corresponding dollar amount. It works out to 1.30xx for the same dates so assuming they used the same interbank wholesale rates, in this case, Amex is better than the Sony Visa.

Also drew money out of my eTrade account using their platinum VISA debit cards at ATMs. Those were very close to the daily wholesale rates published on x-rates.com.

A couple of cards I didn't use is an MBNA Visa/Mastercard because I'd heard MBNA was also imposing 2-3% and if I'm paying the higher rate, I might as well get some reward benefits, which the MBNA cards I have don't offer.

Also I have a credit union VISA which I haven't used for years. Probably will offer the best rates but no rewards.

Oh well, on my $600 hotel bill, the Sony Visa tacked on about $18 in additional fees. Probably not worth it but if you have a rewards card, you might as well accumulate those rewards.