Pros: Fast and relatively inexpensive for an HGST drive. Too early to assess reliability. I'll update as needed.

Cons: I'm using two of these drives as part of an archive (mostly offline, accessed via toaster). Both are reasonably quiet, except for a single "tock" noise every five to ten seconds that the cheaper Seagate Archive drives don't exhibit. Update: ended up purchasing a third one of these drives before learning that one of the other two was throwing SMART warnings about impending failure, over and above the bad blocks revealed by a surface scan. Rechecked the drive every month or so, with the same results. I've returned that drive to the manufacturer after getting an RMA. I'll likely stick with Seagate and WD from now on.

Pros: Cheap. Didn't own this long enough to assess its reliability.

Cons: Periodic, relatively loud buzzing noise. Returned for refund after several hours of testing. I'm using 8TB drives as archives, mounted in a toaster, mostly offline but in a room where the noise is disruptive to two people while in use. Other reviewers have commented that a firmware update solves the problem, which is nice if you have a Windows PC to install it in to install that firmware, *and* don't mind the idea of having to "fix" a newly-purchased product in order to make it acceptable for use. Seagate: fix your drives before you sell them.

Overall Review: I wouldn't recommend this product at all. If I knew for a fact that the manufacturer had begun shipping it with firmware that definitively eliminated the defect, I might try it again.

Pros: Small. Perhaps I can open the enclosure and swap in a new mechanism that doesn't fail within two years.

Cons: Bought this drive in July of 2016, for use as an always-on Time Machine drive, connected to my iMac. I'm now starting to get "failing" warnings in two SMART-reporting utilities, not too long after the two-year manufacturer warranty has expired.

Pros: Inexpensive, easy to install.

Cons: Failed after six years of minor use.

Overall Review: Bought one of these new in 2011 to replace a MacBook's stock hard drive. Computer has seen relatively little use in recent years. Drive failed yesterday (6/3/17) with no warning or audible symptoms, and is now again running on the stock drive that came with it. I suppose I should be happy I got six years out of the WD, but how long are these things supposed to live?

Pros: I've had this drive for about a month. Excellent capacity at a very good price. Using it as a Time Machine drive for a new Mac. Have not subjected it to extensive use, otherwise. I'll update this review should any conditions change.

Cons: A minor detail: the activity light is subtle, but perhaps too much so. It could be more indicative of reads/writes and differentiate better between mounted/unmounted states.