[Greenbuilding] Solar powered attic fans

[Beatrice Dohrn]

Hello all.  

I am looking at solar powered "attic" vent fans for installation in a mini attic that I will have. 
I was wondering if anybody had any experience with any of them.  My particular bugaboo is that I want it to be  QUIET. And manufacturers  promises to that effect seem often to be meaningless,  so I wonder if anyone has any experience to share.   I am assuming that the effect in summer will be worth the roof penetration...    
For some reason I like this one:  
 http://www.bigfrogmountain.com/atticfan.html
then there's this one:  
http://www.myhomeenergysolutions.com/solex-attic-fan.html
and 
http://www.getwithgreen.com/2007/07/09/new-roof-evaluating-solar-fans-here-is-a-list-of-solar-fan-products/
THanksa in advance,  
Beatrice Dohrn

(Eugene, Or)