I like that it's easy for customers to access their account information online, as well as being able to send in payments via snail mail or email when needed! It would also make sense if they had an app similar to Apple Pay where you could use your phone number instead of having to add another form of payment option (like PayPal).
Also, there should really be more options available with regards to customizing notifications. As mentioned above though - this does look very promising once everything comes together properly!! The main benefit so far has been how user friendly it makes sending invoices easier than ever before by allowing users to easily track all transactions without needing constant reminders from our staff members.