Pros: Zalman has won my loyalty. I purchased the gigantic CNPS9500 heat pipe and fan in 2/2009 for the Q8400 that I have been using since. That CPU cooler is still going strong. I was happy enough it that when a five year old no name case fan died, I bought a Zalman to replace it. This is the third Zalman fan I've purchased, to cool three SATA drives that get rather warm without a fan. All of the fans work seamlessly with Speedfan and PWM control.
Summary: Not really a quiet fan but it can move lots of air when driven at full voltage. There are much better fans available for quiet operation. Might be worth buying just to get the silicone fan mounts.
Pros: Moves lots of air at full speed but quiet with speed reducer. Includes silicone fan mounts.
Cons: Not quiet unless speed is reduced. Uses a resistor for speed control. /*/time warp/*/ How 1960's is that?
Summary: A cheap, standard, no-nonsense fan that works decently. The noiseless connector and silicon pins are a nice bonus. I don't use the connector personally, as I have this hooked up to my fan controller, but I can say that while it's quiet at about half-speed, at full speed it gets pretty noisy. So I recommend using the noiseless connector if you don't have a fan controller.
Pros: -Well priced, -Quiet with noiseless connector
Summary: I'm happy with this fan. It was relatively quiet just by itself, and with the noiseless adapter, which lowers the speed by about 1000 RPM, I can barely hear it at all. Even with the lower speed, cooling power is still adequate. I have an Intel 2600K with stock cooling. The processor reached 71.5C under load without a case fan, 65.5C with this fan as a rear exhaust fan, and 68C with the noiseless adapter. I wasn't impressed with the silicone pins.
Pros: The noiseless adapter is effective.
Cons: Silicone pins are a good idea, but didn't work for me.