Abroad with Monzo
I'm in Spain this week for ApacheCon, and Monzo is definitely delivering on the promise - no foreign usage fees, just the MasterCard exchange rate. I got some cash out when I landed, and the rate was â‚¬1.16 for a pound. The Post Office seem to require a minimum spend of £400 to give a worse rate (â‚¬1.1266 for a pound) - and who has time to get their holiday money in advance in this day and age?
As ever with these things, avoid ATM and chip and PIN machines offering to charge you in GBP - they're highly unlikely to give a better rate.