I used to run a couple of hundred servers and workstations with SLES and openSUSE with btrfs for /. Just SUSE's vanilla supported setup, and user data on smb/nfs filers. I tended to forget that btrfs was even involved. I can't remember a single time btrfs gave us any trouble. But snapper snapshots saved a customers ass on one or two occasions.. That was several yeas ago. I also imagine that btrfs has only improved since then.