I'm using ZFS on my FreeBSD laptop. Snapshots not only make backups safer (by making sure the complete backup is taken at the same time, and by zfs sending and receiving them), the boot environments feature also make upgrading safer.

I also really like that I don't need to partition my disk, if it turns out that /tmp needs > 10% of the disk for whatever reason: no problem!

And as I like my data, I appreciate checksumming and copy-on-write.

I haven't noticed any bad slowdowns compared to ext4 on my Debian laptop I used before.