> I'm at pretty much a loss as to why anyone who doesn't specifically need something that btrfs and btrfs ALONE provides (writable snapshots from the top of my head although I'm not sure how that's different from a zfs clone.. One command?... I'm sure I read something cool about 'cp' being faster or whatever; is there anything else?) wouldn't go with ZFS instead.

Licensing: the ZFS license is, last I checked, incompatible with the GPL. That makes it a non-starter for me at least.