Pros: This sucker moves air. I had one of these about 5 years ago. If you put it on a desk flow side down, it will literally hover. I used this when I was overclocking AMD Athlon XP's; coupled with a good copper heatsink, it would rival most water cooling setups.
Cons: Loud. Use a fan controller. If you buy this thinking it will be quiet, that's your own dumb fault. Don't say I didn't warn you.
Pros: This is the most awesome fan I've ever seen. Just make sure you have a way to use the RPM regulator. You don't even want to try and run this fan at full speed. It will cool your apartment. As long as you use the RPM controller, a very quiet fan.
Pros: Moves a LOT of air. I mean, 92mm at ~5000rpm moving 110CFM. It's extremely powerful, and will work terrific at sucking out of a small custom case I'm building.
Cons: Noise and power draw. But I'm not complaining, I knew this before I bought it. If noise is a factor at all I wouldn't recommend it, you might as well get a lower rpm or larger diameter fan than waste energy turning this one down. And you should of known it was gonna be loud before you bought it.
Summary: If your application demands massive airflow, this is the fan. 90mm. At a whopping 119cfm of air you could almost dry your hair in front of it. Excellent fan, but the noise will keep you awake at night in a home system.
Summary: Nice big and fat fan that is designed for serioud airflow situations. 9cm is a great size for most applications. However, not really designed for home users as it is almost as loud as the vaccuum. Down due to noise, but great airflow.