GWS versus Pertex Shield for a sleeping bag?

[repins05]

Comparing a Western Mountaineering Bag with GWS versus a Feathered Friend with the Pertex Shield.

GWS does not seem to be completely waterproof and is rated as "water resistant".

Pertex Shield appears to be waterproof.

Does anybody have feedback for the two? I lean towards waterproof because I am in the rainy northwest. Does the Pertex breathe well?

 

[rcb2000]

Pertex is what Stone Glacier uses, for sleeping bags and the Grumman puffy, that I have. Its plenty breathable, and definitely water resistant.
No experience with what Western Mountaineering uses, but I wouldn't hesitate for one minute to use it.

I also like the 'feel' of the Pertex, dont stick to your skin like some fabrics that Enlightened Equipment uses in their quilts.

 

[Aluminum Rain]

A quick scan of the WWW says that pertex has a rating from 10,000-20,000 mm/24hrs and goretex is rated at 28,000. So the gore should be better. Theres no such thing as waterpproof unless its a rubber bag. Your mileage may vary.