Excellent!!
First of all, I would like to mention that I have a huge case.
I have owned the Thermaltake Core X71 Tempered Glass Edition monster case since 2019.
This case came with the stock 2 front 140mm Thermaltake fans for intake, which were from somewhat decent to indifferent, and one more 140mm at the back for exhaust.
So while playing the latest titles like Crimson Desert, I saw that they could not keep up and that my temperatures were hitting the ceiling, like 80+ on the GPU. (I didn’t particularly care about the CPU because I have liquid cooling and it was handling itself just fine.
Apart from the high temperatures and their INCREDIBLY loud noise, after a lot of research and with Gemini’s help, I chose these.
I bought 3 at first to replace the stock ones I had and was extremely satisfied, but then I said to take it one step further and get another 3.
To cut a long story short, I have dropped 30 degrees on the GPU compared to before, I play games like the ones I mentioned such as Crimson Desert, a bit of Call of Duty, Battlefield 6 and some GTA V, and the settings are always on High. I have never exceeded 60 degrees on the GPU because now the AirFlow is real and the air refresh actually works.
I also bought an Arctic Fan Hub and connected them all together and set them to run with a Curve.
If you couldn’t hear the GPU working, you would think the PC is turned off. I have never had a quieter machine!
The fans have rubber on their edges to absorb any vibrations and resonances with the PC case.
Of course, I also tried running them at 100%, and the machine feels like it is taking off for the stratosphere. They will never need to run at 100% because their operation is efficient even up to 60%.
If for some reason they start running at 100% (while they are set with a Curve), then something else is to blame. Maybe some thermal paste, either on the CPU or the GPU, depending on where you have set the Curve.
In short, I am maximally satisfied; I bought the set of three for 72 euros, while the other set, which I bought directly from a store outside Skroutz, I got for 84. Worth it, the PC feels alive again!
I was between Noctua and BeQuiet. The ugly Noctua fans, apart from being ridiculously expensive, have almost no difference in performance compared to the BeQuiet!
I recommend them without hesitation!!

This fan is a very high-quality product. You can tell right away as soon as you hold it in your hands, it is very sturdy, with excellent construction. I have bought and installed three in the classic arrangement (2 in the front for intake and 1 in the back for exhaust) and I can say that it cools the case very effectively. Now, I don't know if it matters to mention temperatures as they depend on each person's system, the case they have, whether they overclock or not, and the season we are in. Compared to my old fans, the temperature must have dropped by around 5 degrees. Maybe even more.

Now, in terms of sound... things change a bit there. You can't call them silent. Especially the High Speed version that I have, it starts to be heard at around 750+ RPM (about 30% of its power). Of course, my case is designed for airflow, so maybe someone who has a more "closed" case will start to hear it at higher RPMs. If it goes over 1000 RPM, I can say that it is quite audible. But I don't really mind as it does a very good job in cooling, and its so-called "sound profile" is deep, so it is less annoying than other fans.