Both are CoW filesystems with different strengths and weaknesses. BTRFS is part of the kernel, has interesting integrations with systemd (and possibly better L

Both are CoW filesystems with different strengths and weaknesses. BTRFS is part of the kernel, has interesting integrations with systemd (and possibly better Linux tooling in general), and has more flexibility with adding and removing disks (for now). ZFS has (arguably) better reliability and has more built-in features like encryption, read/write caching, and exposing virtual volumes. I don't think folks should default to using one or the other, everything depends on your workloads. Ext4 might even be the best choice. Though bcachefs could be an "endgame FS" if it delivers on its promises.