bcachefs's caching (foreground_target, promote_target, background_target) seems more straight forward than ZFS's ZIL/L2ARC stuff since with bcachefs you can use the same device for accelerating writes and reads of frequently accessed files, while (from what I understand) with ZFS you need two partitions, one for each. I'm not a ZFS expert by any means so maybe I've got the wrong ideas, but bcachefs seems a lot more elegant and straight forward in many regards. Still, I'm not jumping to adopt a brand new filesystem.