As stated in the review:
As for noise, I really didn't notice it putting out much more than your average fan. When listening real close to the fan, you can hear a high-pitched whine, but this is not noticeable when inside the case.
I've come to think that average
is never a good sign, of anything really, and so I'm a bit skeptical as to what the end result (usage in a quiet pc system) might be, don't expect any wonders at least...
But that aside, I really like the looks of those fans, if only they'd make lower-rpm/more quiet fan solutions, then I'd be hooked.