I was won over to btrfs for my new NAS (~6 years ago!) when I saw a demo (which I expect is also valid on zfs) where the presenter starts with a mirrored setup,

I was won over to btrfs for my new NAS (~6 years ago!) when I saw a demo (which I expect is also valid on zfs) where the presenter starts with a mirrored setup, finds the exact block offset location of the file's contents and then overwrites a byte in it with a zero using /usr/bin/dd against the raw disk, /dev/sdX. He then reads the file, uncorrupted, with a kernel warning about a bad checksum that was fixed (from the mirror) during the read. This demonstration is why I switched to btrfs (and ECC) for my new home server/NAS. That, along with compression sealed the deal. I was disappointed about not having dedupe at the time, but it probably really wouldn't have saved me that much space. (I keep meaning to run the dedupe tool to see what it might save me now.)