I received an e-mail a couple of days after I enrolled asking if I had any questions and that I could contact a specific person for questions. It's great to have a breathing living person that I can go to with ease (in case I don't find help in the forums/faq/help section)
Invoice Generation System fed from our main LOB application
We have a system that keeps track of customer billable time. At the end of the month our hour tracking program sums up all client time and automatically creates an invoice for each one using Xero's API.
Integration was done in less than a day thanks to the Xero API and an open-source wrapper for .NET that the company hosts on github.