Our business has been slowly replacing our various storage solutions and migrating to FreeNAS. We had previously used a mix of proprietary solutions including Drobo, Synology and OSX Server. After much investigation and testing, we found that FreeNAS suited our current needs and would be the most likely candidate to satisfy our future expansion.
We manage our own on and off-site backup and have been using Bittorrent Sync with great success. FreeNAS features a BTsync plugin but I have found that the setup is not quite as straightforward as it could be. Especially when you have a number of different datasets and user permission configurations.
I wrote this installation guide for our internal wiki at work and would like to make it available to anyone running into problems with BTsync on FreeNAS.