I've just tried a Unison sync and got around 3MB/s. That was transferring a lot of small mail files, where you would expect overhead to be a problem. With a single large compressed file, I get around 1.3MB/s, so Unison is certainly capable of more than 80KB/s.
You can reduce the SSH overhead by switching to a less CPU-intensive cipher. I have set the default to blowfish, by adding "Cipher blowfish" to /etc/ssh/ssh_config on both machines.
"Insanity: doing the same thing over and over again and expecting different results." (Albert Einstein)