The one thing I really dislike is the way transactions are brought into the system. I get that it's preferable to outsource that to entities that specialize in it, like Yodlee/Plaid/whatever, but when I get to that IFRAME asking me to enter my banking credentials... sorry, I just can't bring myself to do it.
I understand banks are probably unbelievably slow to support standard authorization schemes like OAuth, but of all the credentials for me to get sloppy with, my bank credentials are pretty much at the top of "no way" list.
Any chance as an interim you could support manually importing CSV?
(And yes, beware of the non-paying "customers" that like to suggest the _one_feature_ they need...)