Raven, that must be an old article. Pertex was owned by a firm whose name escapes me, but went bust some years ago. It then was taken over by another firm and there were some issues, but now it's under new ownership and all is well and they are manufacturing again.
Surely you don't want the material to be too breathable? If it is, the moisture will just go straight into the down?
Take a look at the site http://www.pertex.com/ then click on fabrics, endurance.