I use Emma and I think it's very similar although it uses OAuth so I feel happier from a security standpoint. The lack of universal coverage is irritating but hopefully will get there.
One question, what is the joint functionality you'd like to see? With Emma my wife and I can both add our joint accounts to the app and see that in conjunction with our personal accounts and personal credit cards. Are you suggesting you'd like to share your personal/sole accounts with another person? I can sort of see the attraction but can also see how that could create privacy/consent issues that the banks and dashboard providers would be uncomfortable with.