Comment by dspillett

IIRC rsync uses your default SSH options, so turning off compression is only needed if your default config explicitly turns it on (generally or just for that host). If sending compressible content using rsync's compression instead of SSH's is more effective when updating files because even if not sending everything it can use it to form the compression dictionary window for what does get sent (though for sending whoe files, SSH's compression may be preferable as rsync is single threaded and using SSH's compression moves that chunk of work to the SSH process).