I was worried about the noise, but find that it is not objectionable. It uses the Delta 7k rpm fan as the FOP38 but does not come close to the resulting in the complaints I have read about the FOP38. I do not see any justification for anyone returning the Vantec due to noise.
I have an ANTEC sx830 case which already has 2 fans, to which I added a 80mm Sunon hiperf fan. The Vantec is a noticeable presence but blends in with my other fans. The case is large, well ventilated, solid, and is under my desk.
Hours of use do not audially fatigue me. Love the wide spring clip.
BTW, got great deal from Sidewinder: $19 for fan, $10 for Arctic Silver, $4.75 shipping, and note that fan comes with 4 to 3 pin adapter.