I'm on the fence about the Corsair Quiet editions. Personally, I would rather buy the performance editions and just dial down the RPM to an acceptable level - but if I wanted (or needed) the extra performance, I could ramp it up. That is my own personal preference, though, any I am not sure how you intend on how many fans you intend to buy, or how you intend to control them. (Via motherboard, or hardware fan controller?)
Back to the Corsair fans, I bought an SP120 Performance edition just to try out, and even at full tilt it is not as bad as you'd think. I mean, when it's on, the noise is definitely there, but it's not invasive. Some fans have an annoying whir, or clicking, of the motor, or a prevailing "whoosh" as they push the air, both which can stand out. This was a pleasant mix of both, but it's still there. The max RPM is 2350, and when it's at 1800 I can discern it from my *five* Arctic Cooling F12s, which is a very affordable alternative for quiet fans.