Since you've been using ZFS-fuse for a time now, can you report here or blog about its stability? Has the daemon crashed on you, while taking a snapshot, or while "scrub"-ing?
How much data have you passed in?
First, note that the version of ZFS-FUSE which I am using is not a particular release, but this revision from the official git repository. I have not bothered to update my ZFS binaries since January, because I didn't encounter any problems.
The "zfs list" output for my pool shows that I am using 352 GiB. The pool consists of two 465 GiB disks in a mirror setup.
NAME USED AVAIL REFER MOUNTPOINT nas-pool 352G 105G 24K /nas-pool nas-pool/archive 118G 105G 71.1G /nas-pool/archive nas-pool/bulk 234G 105G 228G /nas-pool/bulk
The pool is scrubbed by a cron script each sunday night. I have not seen any crashes/hangs during scrubbing. The scrubs have not detected any errors so far.
"archive" is snapshotted every night. "bulk" is snapshotted" only on sunday nights. The pool contains more than a hundred snapshots. Again, I have not seen any crashes or hangs.
Then there is read/write activity: I use it to automatically archive my emails from Gmail (nightly), sync with my dropbox folder (continuously), and to store my mp3s, photos, videos, downloads and backups when I need to. When reading or writing NAS files, I am usually working from my laptop over WiFi which is a speed bottleneck, so this probably doesn't really stress the file system. On the other hand, I do regularly make a full off-line backup of the "archive" filesystem by hooking up an external USB disk to the NAS. I haven't seen ZFS crash during any of this.
From this, I conclude that ZFS-Fuse is pretty stable.