This technology has been around so long... It surprises me that people just don't get it. Anyone familiar with Unix will understand. Rsync is a magic prodigal & Acrosync has tapped into it from the outside. I used to use the old DeltaCopy and it was FREE but, it does not work anymore, unless your system is really OLD. Plus, it was really slow even without SSH.
I transfer huge files & small files at full Gigabit speed. No, I do not use SSH, internal network behind a firewall PC.
Yes, you have to have a Gigabit network for it to work this fast....