Some non-obvious factors around integration with the current account are key. When you run a small business your pay tends to not be regular in either size, date, or even mechanism. Pay will be made up of a combination of salary and dividends, with salary potentially being relatively minimal and thus requiring supplementing from dividends. Dividends tend to be paid less frequently, perhaps quarterly. And while the minimal salary may be more stable the dividend will fluctuate. Therefore the integration between the business and current accounts should take this into account, allowing this fluctuating income to be “smoothed” - basically hiding the complexity of the fluctuations. At the moment this process is fairly horrible for a few reasons. Firstly, various aspects of the current account break when you send several thousand pounds through it temporarily, en route to a pot. Additionally, with my current bank at least, setting up a BACS Direct Credit for just one person is… “bureaucratically prohibitive”. This means that a transfer done on, say, the first of the month in order to cover BACS Direct Debits won’t actually be there in time, and the payment will fail. So easy access to set up BACS Direct Credits is also key. One clean way that the former part could be solved is to allow crediting of pots directly (i.e. give them - or at least one of them - an account number and sort code). I have further details in a few posts on another thread (one, two, three)
Additionally, for me Freeagent integration is pretty essential, the deeper the better (not just the accounts, but things like sending a VAT payment etc.