Good, quality, and really silent.. but once a year (for the last three years) the technician wants 150 euros.. some spare part "gives out" and there is no maintenance at all but the freezer works.. I haven't looked into it at all, unfortunately..

The motor broke in 4 months from the purchase....... no talk about replacement........
I have been without a refrigerator for 12 days....... unknown when the local service will receive the spare part........
I have done everything imaginable through email and phone......... ''quality'' and ''service'' Liebherr.......
God is with me............
2/10/23 Lucky me... On 18/9/23, I received a call from the local service and they informed me about the replacement of the device... obviously there was no spare part available
On 25/9/23, I received the new refrigerator and since then everything is smooth...

Excellent, indeed quieter in terms of noise level than my old Bosch at 39dB, BUT its noise is very annoying, it is not suitable for an open kitchen, you need to have a separate kitchen to close the door.

edit: 01/09/2023- You get used to the noise, after a few months you don't even hear it.

I have had it (CBNEF 5735) for about a month now.
Although it is an expensive refrigerator, I am very satisfied.
Great cooling, spacious compartments.
The Biofresh (which significantly increases the price) is worth the money because I have seen in practice that it preserves food MUCH longer. For example, packaged salads - opened ones last twice (and more) the time from their expiration date. After several days, they have not wilted or turned yellow.
The same goes for vegetables.
The testing continues.

I also had an experience with the service, which was impeccable.
My first refrigerator was working fine but made a strange noise intermittently.
I noticed it within a week of purchase. A technician came, confirmed it, and quickly replaced it.

As for the noise, it is - I would say - calm. It is not completely silent, but I, who have it in the adjacent room with open doors, can say that I don't hear it at all (in a house where absolute silence prevails).
If you plan to have it in the same room where you sleep, you will hear it with low (varying) intensity.
Its fan does not turn off, but it is quiet to the point where it can only be heard within one meter from the refrigerator (the slight noise comes from the compressor).
In comparison to another (similar-sized) AEG refrigerator (3 years old) that I have, in which the fan can be deactivated at will, I would say that with the fan off, it is slightly quieter than the AEG when the compressor is not running and slightly louder when it is running. But with the fan off, the AEG accumulates ice on its back. With the fan on, the AEG is considerably louder (the fan makes a high-frequency noise that is quite annoying).
Therefore, I would say that overall, it is quieter than the AEG.
It is also (naturally) quieter than a 10-year-old SHARP that it replaced (even though they claimed the same noise level in dB)