Go for it if you're building something bigger than a 4-bay box. It also earns its keep on a busy pool where scrubs and rebuilds never let up, because the 550 TB a year workload rating is there for exactly that. You also get five years' warranty, two more than the cheapest NAS lines. Recording is CMR, the right kind for RAID and ZFS.
!Watch out for
At 7,200 rpm it's from the louder, warmer class. Fine in a cupboard, less fun on a desk.
No Backblaze failure rate for this one. They don't run enough of them, if any, for a figure worth quoting. WD's datasheet puts it at 34 dB idle and 39 dB seeking. Power draw is 6.1 W idle and 8.8 W working on WD's figures, or 53 kWh a year if it spends the whole year idling. Four of them in SHR or RAID 5 give 30 TB usable, or 27.3 TB once Windows has done its binary maths on it.
Specifications
Each value links to the Western Digital page or datasheet it came from.