Summary: I was dubious of their "silent" claims, but these fans really are very quiet. I am using four of them on my wife's electric bike to cool her controller and even with four of them running slightly overvolted (15V each), they run very very quietly. Love them!
Summary: I bought two of these to mount on some hot swap bays that have optional mounting points for a 40 mm fan. The first issue I noticed was that the 2 prong connector on this was considerably larger than the one for the hot swap bay. The pins are almost the same size, but i had to actually cut some of the surrounding plastic from the bay receptacle, to enable this connector to fit. Annoying, but not a big deal.
Summary: I had a bit higher expectations from this fan, but at the end it doesn't has CFM for any serious cooling. But since it is very, very quet (I couldn't hear it), I used couple of splitters and added couple of these fans to blow the air out of the chassis, improving my airflow. So, they cannot be used for serious cooling, but they can help out if placed or right spots.
Summary: I used this fan to replace a stock Intel Northbridge cooling fan. The difference is night and day! While the stock Intel fan sounds like the whine of a jet engine prepping to take off, this Scythe is so whisper quiet that you can't hear it at all. I now have a near-perfect media-center pc. Highly recommended.
Summary: I shut down my media box (AM3+) when not in use because of fan noise. I installed this and now I don't hear it at all. It lets me switch over and watch my Amazon Prime shows and downloads without going through the booting process. Temperature seems fine.