We just signed up for a Plus plan but the Billing form and sent invoices are somewhat broken.
* It seems I can't change the billing email address using the form: after submit, the original email is still set.
* The invoice amount doesn't have a currency symbol: it reads "199" where it should be "$199"
* We are located in France and the form asks for a US state, which breaks the address: "Paris, AL 75002 FR", where it should read "Paris, 75002 FR" (AL stands for Alabama). No big deal, but it would be better if the form only ask for a state if the selected country is the US.
Thanks you very much for the great service, feel free to ask me anything if you need any information about those issues.