To better answer, BTRFS instability should be split into two different parts:
- file structure is totally stable, has not been changed for a long time, and it's proven in multiple places (its lead developers work at Facebook and they use it in many places, and Suse is using now btrfs as their default filesystem)
- userland tools is were development is still rapidly changing, and some tools and options are not stable yet. You can have a better view on the current status here: https://btrfs.wiki.kernel.org/index.php/Status
Do you need specifically some of the feature that BTRFS has? If no, then you are ok with XFS. I'd go for XFS myself probably "today", but who knows in one year.