A disk for NAS at a reasonable price.
It is quiet, you can only hear the disks spinning after waking up from standby for 2-3 seconds. Out of the 10 I bought, one arrived dead, but WD replaced it with a new one within 3 days through RMA.

In terms of speed, it's fine for a 5400 RPM with only 128MB. In RAID 5 with 10Gb/s LAN Aggregation, it consistently writes/reads at around 146 MB/s. With SSD cache, it can reach up to 180 MB/s. The temperature ranges from 25 to 35 degrees Celsius, but I haven't tested it without air conditioning during the summer yet.

The only negative thing I noticed is that it takes about four hours to synchronize and build the RAID in NTFS and EXT4. For BTRFS, it took over 8 hours. I don't understand if this happens only during the initial RAID build or if every time a disk needs to be replaced it will take 8+ hours. Because if it really takes 8+ hours, then every replacement will be a heart-stopping moment, fearing that another disk might fail or that the data in the RAID will become unreadable. Despite being CMR.

Now, if someone wants to use BTRFS for RAID, they should be aware, but I guess it could also be an issue with my setup.

Edit: Now that it's summer and I've seen the temperatures, they reach around 48 degrees Celsius without air conditioning in the NAS with the same 10 disks and only the two 90mm fans running.

Edit2: The problem with the slow RAID in BTRFS turned out to be an issue with the NAS, which was resolved after a newer update was released.

In terms of durability, they haven't had any issues for a year now. They don't have problems with bit-rot or producing errors. They work properly in BTRFS with Clone, Snapshots, and Cold Backup.