In some places I use SATA drives for data storage. From time to time there is a problem with filesystems and I have to fsck, sometimes files are a little bit garbled, etc.
Last time I tried ZFS on SATA disks and to my surprise - just after 3 days I got few hundreds checksum error - well, that explains a lot. Then it stabilized and now from time to time I see occasional errors.
Sometimes we had to live with some problems for so long without any alternative that we have forgotten about a problem and got accustomed to fsck, some bad files, etc.
I would say that ZFS changes that picture radically.
Thanks to ZFS there's no need to fsck, proper data are returned to applications, no mangled fs entries, etc.
It already save our data :)
ps. I haven't yet seen checksum errors reported by ZFS on SCSI, FC or SAS disks...