How many ways are there to copy files from one machine to another...
GNU Tar has a wide range of options. Even without these it's often the simplest way of cloning a section of a filesystem. Use in conjunction with some other mechanism for transporting the tar files from one machine to annother.
Uses the same protocol as ssh. ie. if you have ssh setup then scp should automatically work.
SFTP is an ftp-like frontend to scp. It doesn't actually use or require FTP.