btrfs is suffering from a lot of old bad publicity and some poor design decisions around RAID.
But by now it is a great file system if you don't go near RAID5/6. btrfs has its flaws (ZFS has its own flaws!). However:
- It's used a lot, especially by facebook and Redhat (on fedora)
- Gets a lot of testing
- Sees a lot of bug fixes
- Has a lot of features
I haven't read btrfs code but given that it is a popular file system and Linux code quality tends to be good in popular subsystems I would hesitate to say its code quality is worse than ZFS in any way.
btrfs is pathetic when it comes to performance. So no, thanks.
https://www.phoronix.com/review/linux-70-filesystems
In real world scenarios, where file based backups fail, one needs to add at least lvm.
And only than those benchmarks would be more interesting to me.