I imagine it is a patched up version of a decades old system. But as presented to the end user I don’t think it’s half bad. I much, much prefer the style and features (and proposed features) of Monzo and can see myself switching to Monzo when it launches it’s current account.
But I actually prefer B to Starling and any other start-up app bank I’ve tried or looked in to. I find it much more usable than Starling and I prefer the app (although it could be a little more responsive!)
Starling to me, doesn’t feel like a bank - it still feels like a pre-paid card. The ‘top-up’ element, etc.