Most important is that I can see my donations in real time with an easy access to all information about donation from anywhere at any moment of day or night! There are some features which could be improved like integration into accounting software (like Quickbooks).
It's not enough for me as it should have more options such as sending invoices directly after receipting so there would no need additional support team work afterwards - just send them straight away without waiting till next month when they will do everything manually again because their system doesn't integrate well yet?