You want maximum reliability? Just connect another box and put them to another location (e.g. in your office or at home of the managing director).
All files are synchronized automatically. If one box fails or the internet connection breaks down, the second box takes over the receiving of mails or providing a web user interface. If all boxes are available again all files are synchronized after a short time.
You have to share email addresses & files with your business partners? Just create some logins for them and you partners can access these objects. If they are using as well a BranaBox, they can synchronize there shares onto their boxes. All shared files which are change on the boxes of you partners are synchronized to your box. Even mail addresses may be shared in this way.
For your PC or Mac you can install OwnCloud-Client and synchronize some folders or email addresses automatically. Changes on the PC are copied to the box, changes from the box are copied to you PC.
You smart phone can be synchronized with Folder Sync. You may back up your photos or messenger files in this way easily.