Interesting story:
I picked up 7 of these drives 15 months ago for my NAS, with 6 going into my ZFS pool as a Z2 vdev. These were added to an existing Z2 vdev of 6 x Seagate 2TB drives that were shucked from the Backup Plus Slim externals 33 months ago.
The 2TBs have been flawless all the way. The 4TB drives, on the other hand, started going crazy about 2 months ago after I switched from a custom horizontal-mount assembly to vertical mounting in Icy Dock caddies. Tons of pending sectors reported which would cause ZFS to drop several of the drives, only to clear up after a full disk dd write of zeros, with no bad sectors reported. A few weeks later, this headache would repeat. Old data was fine; new data written in the weeks after the mounting orientation change would occasionally get damaged beyond ZFS' ability to recover.