I bought 2 4TB disks for my NAS. Initially on ASUSTOR and then transferred to Synology. After 3 years and 1 month, one of them failed. Synology notified me that the S.M.A.R.T. detected an error.
I spoke with Seagate in the chat and informed them that it broke 1 month after the warranty, asking if they could do something. They informed me that the disks have a 3-year warranty from their manufacturing date, not the purchase date, which put me 5 months out of warranty. The purchase date is only taken into account for authorized resellers and not all stores. The store where I bought it is not an authorized reseller.
Nevertheless, after a few questions they asked me, they offered me a free replacement even though I was 5 months out of warranty based on their records.
Additionally, I should mention that I had lost the receipt and the store sent me a copy (from 3 years ago) within 2 hours of my email.

Overall, although I was disappointed with the faulty disk, primarily the response from Seagate and secondarily from the store, my experience with the disks is 5 stars.

It is an excellent disk. I have 2 identical ones in my possession on a Synology Nas (DS220j)! It has exactly the speeds it promises. It has not had any problems for almost 5 months. It is located inside a Nas, open 24/7. Operating hours: 3214 hours (1st) [the second one has 1577 hours]. I have filled it twice and emptied it. I have the 4TB model. It constantly writes because I have the cameras sending all the footage to this Nas. So far, it has proven to be flawless. I have done many tests and it has not shown any issues. I will update my reviews after 1-2 years when I have made fair use of the disk.

For the accuracy of the test, I will try to be as objective as possible, and I will run tests on both simultaneously with the same frequency (test), same temperatures, and generally the same conditions on both, so that the results are as "clean" as possible. This is my review so far.

Thank you very much for your time.

Information:

[Bad Sector Count Disk 1: 0 (5-17-2021) AVG Temp: 27 degrees Celsius]
[Bad Sector Count Disk 2: 0 (5-17-2021) AVG Temp: 28 degrees Celsius]

4K NATIVE HDD: NO
DISK Storage: 3.6 TB (3.58TB)

Purchase 04/09/2019
Obviously, it has not been a considerable amount of time since the purchase for a reliable evaluation, but I am mentioning my impressions so far and the reason for choosing it.

- It was purchased as a replacement for an older hard drive as a precaution because it had reached its 5-year mark, and its use is exclusively for backups (not for daily use/torrenting/editing, etc.).
- Due to the importance of backups, I only considered NAS drives, not lower categories that are intended for mainstream use and lack certain security features, such as greater resistance to vibrations.
- It was chosen instead of WD Red because in recent years I have not had a good experience with WD Blue compared to the equivalent Seagate Barracuda drives (partly due to the overwhelmingly higher usage percentages of Seagate NAS drives by YouTubers/tech sites abroad).
- Unfortunately, I do not have a corresponding WD Red drive to make a comparison (as you can find in the reviews of Barracuda/Blue 2TB drives), but so far it has met my expectations.

Benchmark:
https://www.userbenchmark.com/UserRun/21429638