Too much noise!!! Very bad. I made efforts, I put double-sided tape, it still makes noise and I just took it off. I will buy another brand, wasting money

When you want to cool down the inside of your computer, you need airflow. Some people pay for the lights on the fans, others for the noise, but if you have to spend 100€ to have airflow without noise, better get water cooling instead.

I chose these (3 in total) because compared to many more expensive ones I saw, they spin faster and circulate more air. End of story!

Regardless of the selling store, I consider their price to be steep and generally there is a lot of precision in fans.

It makes quite a bit of noise, and it is good to take the 7 volts from the power supply to make it a little quieter

It's worth its money, but don't expect much because for 7€ (that's how much I got it) it makes a lot of noise and the LEDs are not the best

Efficient but makes a lot of noise compared to the others I have on my computer, so I will replace it.
Edit: I replaced it with a Thermaltake pure 12 red 19.5db and I simply found my peace.. the deepcool was making too much noise.

Well, I'm always good at my evaluation! I will give it 5, but I also have some negatives!
Positives:
Beautiful
Good quality
Nice LED
Good air-flow
Very good price for what it offers
It has both molex and 3-pin..

Negatives:
It's not silent, but it's not noisy either, but for people who want quietness, it definitely makes some noise..
The LED doesn't have a particularly strong light.. But okay, anyone who has a glass case will definitely be even more beautiful with this light that the LED gives..
That's it!!

I hope I helped!
I will come back for an update if something happens!

Quite good fans, I was looking for something with good value for money when I built my PC and now, after 7 months, they are as quiet as possible with very good air-flow. I think they are quite good for their price. That's my opinion. If you are looking for a relatively good fan, get them and see.
Update.
After 1 year, they are making noise and I believe I will replace them, but I also made a mistake and accidentally punctured a piece of their plastic, so I think that's why they are making noise.
You can see them in action here: https://www.youtube.com/watch?v=hOcqWFaAsh4

Best choice for the money, not the first one though for those who want a quiet computer.

Edit: After 3 years of gaming use, they haven't had any issues (expected). However, on a Ryzen 5 3600 stock cooler, they reach 80°C in GTA V and 90°C on the GTX 1060 6GB. Quite noisy. Do yourself a favor and spend an extra €2 and go for the BeQuiet Pure Wings 2.

Very good case fan.
In the positives:
1. It has very good airflow even at low speeds. (in idle, GPU temperatures have dropped about 4-5 degrees since I installed them and CPU temperatures have dropped 1-2 degrees)
2. Good build quality.
3. The blue LEDs (although I'm generally not a fan of LEDs) are quite nice and relatively discreet.
4. Good price.

In the negatives:
1. They make quite a bit of noise at high speeds. However, you can adjust the speed according to your preference.

Overall, a very good value for money product and I would highly recommend it.

Very good airflow, good construction but not exactly quiet... Especially at maximum speed it makes quite a noise.
However, for its price, it is a fair choice.