I don't need to backup my boot sectors or root partitions since all my systems are provisioned. I can always re-create them with scripts, should any of them fail.

I'm only replicating the data filesystems.

From what I see, sanoid looks quite similar to zrepl. Both tools are probably able to achieve similar results.

I do feel that zrepl has more features so far, though. But hey, if your setup is working and your data is secure, that's the most important.