A few things stand out for me:
For a long long time Monzo charged 3% on ATMs withdrawals abroad over £200 on a rolling 30 day period. So if you took out a grand over your holiday you would be charged on the £800.
Very recently they dropped this for inside EEA but still charge outside these places.
However Starling remains fee free regardless of where you are in the World.
The other key thing is depositing cash.
Monzo restricts you to a max cash deposit of £1000 every 180 days and pass on a charge of £1 for using PayPoint. So if you had a few grand to deposit it would literally take years and cost you.
Starling works with the post office and is free to deposit. With minor posties they’ll take a few grand, if you’re in a town they can take £20,000 in one day.
Not a deal breaker but they pay 0.5% AER up to £2,000 and 0.25% up to £85,000. Whilst Monzo pays nout.
If you need Starling you’ll generally get through to someone to live chat in minutes. With Monzo its more a case of and no longer live chat, conversations could be minutes or it could be weeks.
With all that said I still use Monzo for non-Amex and ATM.
They will become useful again when they integrated Credit Cards into the budgeting and I can stop using Yolt.
At the moment Monzo is annoying me on many a topic, with its wishy-washy approach to Plus accounts its lucky dip Overdrafts/Loans and how its handled SCA. I also think the app redesign is a mess.