Oh dude, it seems doing its work well. Mine is not that state yet, but I do vacuum once in a month.
Do you live in Beijing now? Btw, happy new year : D
Yes they have two precise models, one looks like speaker and the other one, which I bought, looks like subwoofer.
It's not noisy, actually I put that on my desk as well so normally all the sound I heard comes from PC case = .= And I don't bother to turn off so I guess it won't cause any...
I'm tired of with buildup dust in PC cases and have to clean the filter and keyboard with brush monthly. So I just get rid of every cleaning gears and buy a Clair TD1866 (www.go-clair.com).
My logic goes like this: dust from computer is mostly from your room, so if you keep your room perfectly...