Best rsync options to transfer data between two Mac
Personally, I'd be inclined to drop the z switch. Compression is only really useful over very slow connections (mobile data, dial-up) as the CPU is likely to become the bottleneck. I've certainly seen a drop in throughput with compression enabled.
Assuming your network is trusted, you would do well to use a more efficient, but perhaps less secure SSH cipher as this will probably speed up the operation a little (it certainly helps with VNC over SSH, or X11 forwarding over SSH).

Run ssh -Q cipher on both systems and pick a cipher common to both
Use it with rsync -vhaHE --progress -e &quot;ssh -c aes256-cbc&quot; andrea@imac:/remote/dir /local/dir/ 2&gt; errors.log

PS: I also use the -h switch to get more human readable numbers in MB/s as opposed to b/s