Currently, I use Btrfs on Synology, mainly because snapshots and checksums are nice, but I never really did the work to do benchmarks against other FS. In the past my choice was Ext4 or XFS with LUKS/LVM, then Btrfs matured and since then I moved to it. So far I had no issues, but YMMV, some people consider it still not entirely reliable, but I do backups. I'm setting up a FreeBSD server where ZFS was the natural choice, again snapshots, boot environments, native encryption and just maturity/reliability. I haven't considered OpenZFS yet, mainly because my Synology does not support it, but your benchmarks have some interesting numbers, when I'll have again enough money for some new HDDs I may give it a try.