I looked for someone posting on the new cloud system and billing integration. I have not seen any post and think it is imperative that we can get some 3rd party integration ASAP. The ability to seamlessly sync would be great. We use 2 products today for our billing.
For the majority of our billing we use Connectwise and for some of our ISP billing we use Platypus. We have been trying to find a way to collapse the ISP billing back to Connectwise but it does not support Radius. Connectwise has a robust helpdesk, configuration database and billing but just does not support the legacy. They also have pre-built APIs already in use for this for many other 3rd party apps so I bet it would be easy to do.
We use Reflexion Anti Spam and Intronis Backup which both support billing integration to Connectwise.