May I suggest Starlingt as another alternative for UK residents, as Tandem is a credit card and as such people may not be eligible. They also do joint accounts if you’re going abroad with a partner.
They offer the MasterCard rate at the time of presentment, rightly so @neil mentioned this can result in a less transparent rate as it isn’t actually converted until the transaction is completed, it just blocks the rough amount until then. Another thing to mention is if you’re withdrawing a lot of cash, this is especially a good idea, as there is never any fee (just a fair usage limit of £300 a day)
You’ll probably get slightly better rates with Tandem (assuming you qualify) if you factor in 0.5% you get in cashback on their main credit card.
Other alternatives could be a Metro Bank card if you’re in the UK which also offers free European currency spending and withdrawals. Currencies not used in the EEA (or Switzerland) are subject to 2.99% markup as of time of writing.