The Arctic Freezer 7X Co is a very good choice for someone who wants to cool a tray processor or replace their old stock cooler due to noise. It's worth it at €15. However, for an additional €10, someone can buy a Pure Rock Slim that performs better than this one.
Its positives include small size, easy installation, detachable 92mm fan, pre-applied Arctic MX2 thermal paste, and very good build quality.
Now, speaking about its performance and noise level. In the tests I conducted, comparing it to the stock cooler of the R7 2700X (video from the review at the end), under the same conditions, the Freezer 7X Co was on average 5 degrees cooler in a Prime 95 small FFTs 15-minute test. In terms of noise level, it was quieter due to its maximum 2000rpm.
So, the conclusion is that the Freezer 7X Co is worth it at €15 for a tray CPU or for a CPU that doesn't have a good stock cooler. However, I personally believe that it's worth the extra €10 for a better one, especially if you plan to upgrade to a more powerful CPU in the future.
Here's the video where I reviewed it:
https://www.youtube.com/watch?v=JCYpcdlISps