Beautiful and silent! Very good cooling with good airflow and high pressure. Excellent for both cases and coolers. I trust CoolerMaster in terms of quality and performance. I used 3 of these in combination with 2 200mm CoolerMaster fans and the overall result was fantastic.

Yes, but.... Yes, it has good airflow, yes, it has nice colors, but they are not exactly quiet. When they increase the speed, they sound quite normal. The huge downside that made my blood boil was the noise when I placed them on the top part of the PC case for air extraction. 3 out of 3, I bought a set and they rattle when they increase the speed and they are upside down. When I changed the case, I bought be quiet light wings and there the difference was noticeable in both colors (incredibly more intense and brighter) and noise, even when I have them for intake, they make a whistling sound. They are not bad, and if I didn't have the rattling, I wouldn't mind them as much. Reading other owners' reviews and comments, the rattling is random, it doesn't happen to everyone, so I was a bit unlucky. But there are definitely better ones out there!

Certainly it is not excellent but very good and it loses due to color accuracy compared to monochrome ones that have passed through my hands. Personally, I use one color and I am not particularly interested in RGB. I should mention that these specific ones are not compatible with my motherboard and maybe that's why I couldn't achieve the best result with color combinations, dual colors, etc. I used OpenRGB and managed to achieve something better, but for some reason the program creates coil whine on the motherboard, so I set one color and that's it.
The main positive is that at low speeds (650rpm) it is absolutely silent, you have to bring your ear 10 centimeters close to hear the airflow. Up to 1000 rpm, the noise is negligible, while above that it is quite audible, but the noise is quite "sweet". The downside is that the best performance comes after 1000 rpm, which is logical if we consider that we are talking about max 67cfm and compared to the recently acquired Arctic Bionix F14, which is more efficient at the same speeds but annoyingly noisy.
Be careful with the cables because you may need an extension, especially for power. The cables are about 30 centimeters long and depending on the case and motherboard, they are too short for direct connection. The argb has a 5 centimeter extension with a second male connector to connect a second fan.
As for the construction, it is very sturdy, indeed it weighs around 200 grams, about the weight of a smartphone, and you can feel the good quality of the bearing as soon as you turn it with your hand.
Is it worth the money? Yes, I would say that for about 15 euros it is worth it and certainly you won't find most branded argb 14cm fans at such a price.

Not the best construction. I have 6 of the same. One has the sticker crookedly glued in the center, resulting in a elliptical movement when it operates, which is somewhat annoying. The other one came with a broken bearing and it sounds like it's creaking. What can I say! Maybe I was unlucky!

Yes, it may be quiet but it doesn't have the static pressure it claims! Quality construction...steep price! Because I also have the masterfan mf140r....I will say that I prefer the latter! Sliiiightly noisier...but better static pressure and personally, nicer RGB!