BTRFS has been stable for a while, except for RAID 5/6. However you can use RAID 1 for all intents as RAID 1 provides essentially RAID 5/6 and is much more flexible.
With BTRFS RAID 1 you can set the number of drives, and the number of duplicate data, and can use mixed sized drives. Due to this, I would recommend RAID 1 over RAID 5/6 anyway even if RAID 5/6 was fine.
I am using it for years and ceased to run into problems about 3 years ago.
Production ready as in building a business on it. I would not. Storing your personal important stuff (and have backups in place): yes. Unimportant personal stuff: also very much yes.