Speaking personally and not as part of the Monzo team, I’ve found B to be among the better offerings from the legacy banks. I actually worked for Clydesdale Bank a few years ago, so I’m familiar with how their back end works and I know a few people at B. They seem to straddle the line between legacy bank and something like us, in my opinion leaning more heavily towards a legacy bank; they still run on all the legacy tech that the rest of them do.
Right now, they serve as my back-up account; I don’t have any regular deposits with them and realistically the only time I’d use them is if I’d lost my Monzo card and needed to use a card in the day or two before I receive a replacement.
That said, I really dislike their app. I can see what they’re trying to do with it, but the colour scheme and general layout of things doesn’t really fit my idea of good design.
Pretty good telephone banking experience though!