Verdict

These two are closely matched CMR NAS drives of the same capacity - decide on price and warranty. Check the live $/TB above.

ST16000VE002 WUH721816ALE6Lx
Capacity 16 TB 16 TB
Recording tech CMR CMR
RAID / NAS safe Yes Yes
Class Surveillance Enterprise
Spindle speed 7200 RPM 7200 RPM
Cache 256 MB 512 MB
Noise (idle) - 20 dB
Fill Helium Helium
Interface SATA SATA
Failure rate (AFR) - 0.80%
Price / TB $32.92 $43.40

Highlighted cells mark the stronger spec for a NAS build. Failure rates from Backblaze Drive Stats where available; $/TB shows once live prices are wired.