What does deliver higher transfer speed for Timemachine backup to ubuntu? NFS or AppleTalk (netatalk)? I want to do Time Machine backups to an ubuntu server. It is a hosted remote machine, not in my LAN. 

So far, I have found two approaches to realize the connection between the computer and the backup server: netatalk or NFS. Question is: which of these approaches would deliver higher transfer speed? 

I will communicate with the ubuntu server within a ssh tunnel.
NFS is known for higher performance than AFP or SMB; it is also a native protocol for unix based operating systems therefore it should be easier to setup.