In conclusion, I have to agree with Chris and everything he has told me about this company being true as could be. Noctua coolers not only can do a good job of ridding the CPU of its heat, but do it so quietly that it left me checking to see if the fans were even running. As far as tower style coolers go, with a small form factor in mind this is the quietest cooler I have tested yet. I have to say I am very impressed, to say the least. The well thought out overall design of the cooler doesn't just stop there. Noctua takes it all the way into the mounting hardware. Noctuas take on getting a CPU to stay in a comfortable range of temperatures, while leaving the surrounding area virtually free of noise puts this cooler high in my list of favorites I have tested.
Most good coolers fall under the "magic" $50 mark and the NH-U9B accomplished that too. To get the NH-U9B to your house will be just under that mark if purchased at Newegg for 49.99, currently offered with free shipping. If you plan to add the second fan, expect to pay another $19.99 plus shipping to get it to your doorstep. Personally, after dealing with some really loud fans, I can appreciate quiet and I don't feel the $49.99 asking price is unfair.
I keep looking at the Noctua NH-U9B and I'm trying to pick it apart and find something to fault Noctua on. To be honest, I only came up with one issue. With mounting the hardware I try to look at it from all aspects and I found a small flaw with the AMD mounting mechanism, but only if you are considering the dual fan option. The actual latch that puts the pressure on the socket and holds the cooler down sits about 3-4mm too high in my opinion. When using the dual fan configuration, I noticed the fan that is on that side has to rest atop the brace. This forces the fan to ride a bit proud of the top of the NH-U9B itself and might, ever so slightly, effect the cooling potential. But even with this small issue, the NH-U9B has left me very impressed and I have to say, if it fits in your case and you like things quiet, this cooler has to be added to your top picks list.