ZFS on Linux has had many bugs over the years, notably with ZFS-native encryption and especially sending/receiving encrypted volumes. Another issue is that using swap on ZFS is still guaranteed to hang the kernel in low memory scenarios, because ZFS needs to allocate memory to write to swap.

The swap issue isn't zfs' fault though, it works just fine on FreeBSD and illumos... its a issue with how the Linux kernel handles things.

The zero copy that zero copied unencrypted blocks onto encrypted file systems was genius. It’s almost like they don’t test.