Summary: I use this under my work desk to keep my laptop cool. I have to say this is the quietest computer fan I have ever owned. I liked it so much, I just bought an 80mm for an HTPC project that I am building. I recommend this fan to anyone who needs great air flow from a super quiet fan.
Summary: They are Noctua; those who know - know. Moves air quieter than any other 80 mm fan I have tried. I use nothing but Noctua fans in all my systems where they make a compatible-sized product. I may be a bit partial to Noctua but only because they continue to live up to their reputation. They generally cost a tad bit more but you definitely get what you pay.
Summary: I built a gaming system in an HTPC case thinking that I would eventually need water cooling due to cramped case conditions. Four of these fans barely make any noise and I haven't had any overheating issues yet. Wouldn't be surprised if I could get some overclocking going even with the stock heat sink. These are worth the price especially from a durability and low noise standpoint.
Summary: Replaced a very noisy fan in a behringer 1000dsp powering a DIY 15" sub with this fan. I left everything else intact (shroud) and it is very quiet. I have not had any shutdowns. Fits/works perfectly.