It took me less than 3 days for btrfs to fail me, but that was in the 2.6.33_rc4 days. Had it gone better, I might have become a btrfs developer rather than a ZFS developer. In hindsight, I am happy with how things turned out.

We use Suse with BTRFS at work. I don't know of any instance where we lost data, but the weekly filesystem rebalance that runs during business hours and causes the machine to not respond to anything except pings is a little frustrating.

I've been using it for a good 5 years. OK, I had one time. When I removed a disk from a mirror, forced the remaining disk to operate writable as a single, then attempted to migrate it to single disk duplication, then shut it down before it finished migrating.

That's not a sane way to handle data really, I was playing around with unimportant stuff. If it was real data, I would have mounted it read only, and copied it away.

I have not had good luck with BTRFS on systems running on battery. Its been solid on my workstation for a while though. Still, it is disappointing that it hasn't stabilized faster.