Scythe are making some of the best heatsinks about and this one does not fail. It's not for everyone - if you are planning on overclocking your PC then you should definitely get the Scythe Mugen 2 which I have running on an overclocked I7.
I'm running the Katana 3 on a quad core Phenom black and the cpu temp is 60degs when the cores are flat out. The 92mm fan is not silent but at even at 2500rpm (when CPU is at 100%) I hardly notice it! I was dubious about the angle of the fan actually cooling my the transistors and heatsinks around the processor but they are cooler than they were with the original stock fan from AMD so it must be working.
Considering the price, this is a great bit of kit, hightly recommend.