That's nonsense. To start with, the OP already CLEARLY stated they didn't care much at all about aesthetics, so what it looks like is probably irrelevant, besides which, your personal opinion about how the Noctua coolers looks is your own and doesn't come close to reflecting the opinion of the larger enthusiast community.The BeQuiet Dark Rock Pro 4 performs comparably to the Noctua, is cheaper, and doesn't look like a used piece of toilet paper. It won't fit in that case either though. Unless you win the silicon lottery you'll struggle to cool a 9900k with either cooler unless you leave the Asus default TDP enforcement settings turned on in the bios. In that case the CPU will be completely gimped. If you don't at least achieve the 4.7 ghz all core turbo there is no point in buying the CPU. It will just run at base clock under load with the default settings.
Temp wise, not even close. The DRP4 has a 6°C stock idle difference from the D15, a 5.75°C difference in overclocked load temps, and that is a world of difference when comparing supposedly "comparable" coolers. Not comparable. Not even close. In fact, there are NO BeQuiet coolers that compare when it comes to cooling performance decibel for decibel. BeQuiet doesn't even make exceptionally good products. They just make products that LOOK exceptionally good, and then throttle the fan speeds to get good sound level specs on paper. Obviously, if you take two otherwise identical fans, and limit one of them to 500rpms less than the other, it's going to be quieter. That's EXACTLY what BeQuiet does.
Noctua achieves those kinds of sound levels without gimping the fan performance, so at ANY given RPM, they are going to be moving more air AND be quieter, pun intended.
Well, in THIS case, the best of the best is EXACTLY what is called for, so I don't think that cooler fits the bill. It's a good enough cooler for what it is, but it is not in the same class as Noctua and Thermalright when it comes to performance.Typically, this paragraph is filled with dislikes about design or anything we feel might be lacking. However, unless you are looking for the best of the best in thermal results, there is not one thing we can pick out with the Dark Rock Pro 4 which we do not care for.