Not sure about the stats, but it does feel like there are fewer. So from what I know encryption and sending fs state had bugs in ZFS.
And on btrfs anything above raid1 (5,6 etc) has had very serious bugs. Actually read an opinion somewhere (don't remember where) raid5,6 on btrfs cannot work due to on-disk format being just bad for the case. I guess this is why raid1c3/c4 is being promoted and worked on now?
I love ZFS, but have been corrected a couple of times when I said it was bomb proof. Can't remember the details, but it has served me faithfully for 10 years or so? Plus the bugs were pretty niche if I recall correctly.
Edit: found some comments below:
ZFS on Linux has had many bugs over the years, notably with ZFS-native encryption and especially sending/receiving encrypted volumes. Another issue is that using swap on ZFS is still guaranteed to hang the kernel in low memory scenarios, because ZFS needs to allocate memory to write to swap.
And on btrfs anything above raid1 (5,6 etc) has had very serious bugs. Actually read an opinion somewhere (don't remember where) raid5,6 on btrfs cannot work due to on-disk format being just bad for the case. I guess this is why raid1c3/c4 is being promoted and worked on now?