Was a happy Supercard user - used only while abroad - and it saved me tons on overseas ATM fees and exchange rate charges. It was also app driven with a very efficient way to link it to your cards for top-ups, etc. Then they announced it was to be shut down (no wonder - they must have lost a small fortune with that one!) and a quick research into the alternatives revealed Monzo was the best for me at the time, also with a very good app. Signed up mid 2017 and was a beta Pre-Paid user, then went with Current account and Joint Account when they launched.
Loved it so far - and you don’t hear that about banks often. Keep up the good work 