As a follow up to my last post, another benefit of off-site storage using DFS-R is the ability to use namespaces to allow the different locations quick access to the files they need on the file server closest to them.
DFS Namesspaces are virtual paths that use Active Directory's sites and services feature to determine which file server is closest to you and connect you to that server without having to specify the servers name in the path.
For example, if you have a domain (subdomain.domain.com) with two servers at two different locations participating in DFS replication (FileServerA and FileServerB). You can set up a namespace (FileServer). Then, you can write your login scripts to connect to \\subdomain.domain.com\FileServer\Share and if you are in location A your computer will connect to FileServerA and if you are in location B your computer will connect to FileServerB. Say you travel back and forth between locations. All changes you make to a file at location A will replicate back to location B once you close the file so that when you return to that location you have not lost any data. Since DFS-R uses byte-level replication, it is not transfering much data so the delay between closing the file and replication is minimal.
There is always the chance that a conflict will arise by two people accessing the file at the same time and you may lose some changes, but the administrator should be able to look up and resolve these conflicts and hopefully they will be few and far between. However, this is one downside to DFS that should be considered. It would be great if they could add some functionality to the process that would handle these situations better and not require administrator intervention. I am sure Microsoft would tell you to buy Sharepoint.
You will need to make sure your sites are set up correctly in Active Directory, but it works great.