If you're in the US (or can open a US bank account), I've always had good luck with Charles Schwab's ATM card. They don't charge a foreign transaction fee (which is where you really get killed with US credit cards - my Amex Blue has a 2.7% - way more than any difference in spread) and they refund your ATM fees (even foreign ones). Sometimes their system doesn't automatically catch the ATM fees, but it's generally pretty good and I've always had a good experience with customer support getting the missing ones refunded. While I haven't tried to match up the mid-market rate for the exact moment I made the transaction, it's always seemed to be close enough inline with what the range on that date was that saving the $2-5 in ATM fees + no foreign transaction fee if I use it as a Visa would have greatly made up any difference in the spread.
Do UK credit cards generally not charge foreign transaction fees? There are still some in the US, but a lot are either higher end cards (Amex Platinum) or geared specifically at travelers.
Here in the UK they charge on everything, IIRC when I went to USA they charged something like £5 per withdrawl, then the amount you got would also have an expensive spread. The £5 per withdrawl was irritating as it forced you to withdraw $200+ a time, the more you took out the cheaper it would be overall.
This is normally the typical US ATM fee which UK banks don't bother to try and return to you, AIUI. The credit card spread by itself isn't that bad; it's better than almost all alternatives except for pre-pay currency cards (not as secure or convenient as a credit card especially if you get saddled with a big pre-auth somewhere) or shopping around for the cheapest cash conversion (in which case you end up with a wad of high-value notes you can't spend if you're not careful).
From the "guide" that came with a new "Premier" Lloyds Visa Debit card a few days ago: They charge 2.99% on all FX transactions and a further 1.5%, min £2, max £4.50 cash fee.
FWIW my Australian credit card with Westpac charges foreign exchange fees, about 2.5% if I remember correctly. It's only recently that they've added those fees as separate line entries in the account.
Do UK credit cards generally not charge foreign transaction fees? There are still some in the US, but a lot are either higher end cards (Amex Platinum) or geared specifically at travelers.