Major Bug: Caja crashes all the time during samba transfers of large files >4GB under sporadic wifi networks, and when it does, the whole system sometimes becomes unresponsive, and needs reboot. It's probably partially related to ZFS caching not releasing enough ram when needed.
ZFS root cache is too large. Sometimes it takes over 80-90% ram, causing unresponsiveness for systems with less than 4GB of ram, especially during large file transfers. Needs default kernel parameter to limit ZFS caching to about 1GB ram per 1TB of storage. So for laptops with 256GB-512GB SSD, ZFS caching should be hard set to 256MB-512MB during initial installation.
ZFS root mirroring doesn't work during initial installation. I ended up installing ZFS root on one drive and mirrored another to the rpool after installation. But the boot partitions are unmirrored this way. I would rather have Linux ZFS support similar to FreeBSD/Illumos.
ZFS doesn't automatically discover and mount secondary ZFS data pools after installation. I have a script that I run after boot, but when I forget to run that script, I lose the entire Steam library stored on my data pool. Update Zsys for automatic data pool mounting?
You may find that your ZFS issues will be better addressed here:
AFAIK that is not related to a particular FS. Linux grants as much RAM to file cache as it can.