Pros: Nearly silent even at full speed. Includes both low noise and ultra low noise adapter, but without adapters dB still less the 20. Adapters reduce noise by 4 and 7 dB approximately. Would be perfect for a media center PC.
Cons: has power cable extension, but for wider cases or side mount applications cable was just long enough.
Summary: Overall, it's what I expected. They do a fantastic job of moving air and keeping as quiet as you can get at certain speeds but you have to realize they will look like dirt in most cases.
Pros: As expected from Noctua, these fans fun quiet and move a lot of air. They ramp up in speed (but also noise) but that's just the way it is. Comes with a nice extension cable if you need it and adapters to fit your needs if you don't have a controller or a program set up.
Cons: That brown and beige colouring has never looked good in a case. If you want your fans to be seen, these might not look the best in most cases.
Summary: I have now purchased six Noctua fans and all of them have been great except this one. It's very Quiet as you would expect from Noctua but I don't think its the Fan blade magic that's making this happen, it's the horribly slow speed this fan rotates at. I think it's 800rpm and that's pretty darn slow for a fan. The 140mm moves very little air and certainly does not scale up in air flow from it's smaller siblings like you would expect.
Summary: I am using this fan as a top case intake to feed my my CPU cooler. I have its speed controlled by the CPU temperature. It is very quiet and moves a good amount of air. My idle temps are 1c above ambient and my load temps are as good as open case. It is very quiet even under load. A great fan but a tad expensive.