I recently purchased Billed here on AppSumo, and while I like the majority of the UI, it could be better.

For example, I was inputting some previously paid expenses and invoices sent into Billed. While the date of the expenses were different, Billed showed them all in the month in which they were approved. This is a different user experience from the Invoices view. The invoices were different dates and yet they were marked as paid all on the same day. The invoices appeared in the Dashboard in the month that they were supposed to.

This is just something to be aware of when you are putting information in the first time into Billed.