4TB drive recommendations

StephenB wrote:
+1 - I ran into a bunch of Seagate failures some years ago, and stopped buying them. Though you will find posters here who had exactly the opposite experience, and switched from WDC to Seagate.

That's why some people use both, one NAS with WD, the other with seagate.

ST4000DM000 are desktop classe models I think, ST4000VN000 are more suited for the job (but the VN are recent disks and may not have been in the HCL when you bought yours), the price difference is made up for by the power consumption and 1 year additional warranty. Not to mention a lower failure rate (less vibrations + less heat = less failures in theory) and less noise. I own 4 of those ST4000VN000 that ran 24/7 for more than a year, no problem so far.
That said each user has its preferences. I believe that both manufacturers do great job, as long as you pick a model adapted to the use you plan to make of it, you should be fine. If you can buy a spare drive, you will feel safer knowing that you can replace a doubtful disk easily and do all the testing while your NAS still have redundancy. Still you will need a backup system anyway.