I also have a 4412 F/2 GL which I'm using in a Seasonic Super Tornado 400w, and it's a really good fan. As someone else mentioned, its drop in noise output is quite linear in relation to its drop in voltage. I would characterize the sound at low voltage (5-7v) as a bit rough, but it's still really quiet. Also, I can't really say anything about their build quality since I've never dropped mine or anything like that, but these fans are really heavy. Definitely the heaviest fans I've ever used. Their only downfall is that they're expensive. I bought a from Silicon Acoustics a couple years ago, and I think it was around $24
. It's a great fan, not perfect due to it's rough noise quality, but I still like it a lot.
Elaboration the noise quality: I can't really tell you what it sounds like at 12V because I never run it at 12V. At 5-7V, though, it sounds kind of bassy, lower than any fan I've used. The roughness that I refer to isn't really a clicking, it's just kind of a low unevenness. It's hard to describe, but it's definitely passable.