As an IT professional, these Hitachis are my go-to for large storage - This exact model, in fact, though I typically buy hard drives new. These are not the absolute pinnacle of perpendicular magnetic recording technology, and do not have the greatest total data storage density… BUT, they are the best price/storage/performance ratio out there. Way cheaper per TB than buying the newer 6TB or larger models. These outperform Western Digital Red 4 TB and many other drives handily in speed, due to the faster 7200 RPM spindle speed, and at similarly low noise and power levels. Plus, the NAS variants of the Hitachi drives work very well both in regular desktops, as well as in NAS or server settings. They are not perfect, but they strike a terrific balance.
I personally have eight right now; six are running in a RAID array (RAID 10 - I gave up on 6 because of the loss of performance with my RAID controller) in a Dell PowerEdge server for media, and the remaining two are in my desktop, running in an asynchronous backup scheme for photo and video work. Love, love, love them! I used to swear by WD Black drives, or Seagate hybrid SSHDs, but these are easier to trust.
P.S.
While I am not sure about the warranty service on these, I do have a lot of experience with older and used HGST drives. They have proven far more reliable than almost any other brand that I have used in my nearly 20 years of experience with computer hardware… As long as they were refurbished by someone authorised by Hitachi, you should be in decent shape. Their MBTF (mean time between failure) is orders of magnitude better than most competitors, and reviews are far more consistently positive than most anything else out there.
CAVEAT EMPTOR
Despite my singing praises here, I do not usually recommend buying refurbished hard drives. I bought my keyboard, mouse, monitor, PS3, TV, router, server, and plenty of other stuff refurbished, and recommend it in many cases. Having worked in electrical engineering as well as IT, I often feel better knowing that the refurbishing tests are more thorough than initial testing for new products before sale, and therefore my likelihood of having to make lemonade are greatly diminished. This is especially true of Apple products - I never buy those new.
If you can afford to wait, you can occasionally find these on sale for <$160 new at places like Newegg. But if money is a huge concern, these may serve you well. Or you could opt for WD Red 3TB drives.
$0.02 contributed for the day.