Personally, I only got it for data storage. WD is a guarantee and the Blue series is the most value for money. I have had two 1TB and 2TB for years now without any problems. It's quiet, doesn't heat up (its biggest advantage), and the transfer speed is around 120-140MB/s, which is satisfactory. I bought it from the skroutz basket due to their continuous support.

I bought this Christmas '18 disk from a big electronics chain. After using it for 7 hours (with Hard Disk Sentinel), it suddenly started acting up and the health dropped to 40%. I have never encountered this before with a WD internal disk. I went to the store and they immediately replaced it. Since then, everything has been working fine as one would expect from a WD HDD.

I bought this specific disk in the first days of 2020 to replace an older one that was full. The disk is completely silent, doesn't heat up (35C), and the transfer speed is around 140-150MB/s both in writing and reading.

This is the third hard drive I've gotten from this series. I have two 1TB ones and now this 4TB one. I use it for backup and to load movies. It's perfect for this job. No, it's not the quietest hard drive in the world, but in the case I have 1 SSD, 3 HDD WD Blue series and it's pretty quiet with a fan blowing on them. Unfortunately, while the 1TB ones worked at 7200, the 4TB one works at 5400. The speeds it reaches in writing are about 140-150MB/s. I've had the other hard drives in this series for 8 and 4 years and so far they haven't had any problems.

In summary: Get it for backup, loading songs, movies, photos, etc.
Don't get it to put an operating system on it.
UPDATE: The hard drive has left us...times!

I have two of these, one for personal files and one as a storage for downloaded material (with VDSL on the horizon, storage requirements are increasing).
WD is reliable and I recommend it over Seagate (I have had negative experiences with their hard drives - it's not a coincidence that Seagate has cheaper products).
All good with WD Blue!!
Of course, it's not recommended for installing an operating system. If you have the money to buy this, it means you have enough to invest in an SSD, even if it's just 120GB for the operating system. :)

"Too many bad sectors" from the first use. I suspect the entire batch may be like this. It was returned at the store's expense and I am awaiting a response for replacement.

*Update 1: The above hard drive had a manufacturing date of 22/03/18. I purchased a second identical hard drive with a manufacturing date of 02/08/18 and it is working perfectly without any indication of hardware failure.

Dead on arrival on both disks.
The first one I received after purchase, and also the second one that came as a replacement.
I am waiting to see what condition the third one will be in.

Low temperatures and high speeds, but the issue I encountered is that it makes a lot of noise. The noise comes from the rotation and not from the head, so it sounds constantly. Because I have many from the Black series, comparatively the Blue ones have a much thinner chassis, something that is also reflected in their weight. Of course, only 2 years warranty.