Re; waterproof Gortex shells, are a double edged sword, they are less breathable than pertex so can more easily contain/ trap perspiration moisture, reducing the efficiency of down...but even the most breathable shell materials can’t entirely stop the dampening effect of such internal moisture passing across the surface of down.
No maker has offered a "waterproof" goretex shell for about 25 years...
When you think of GTX you normally think of various other competing technology laminates in the same technical performance context.
My words still correctly apply to any pre-existing GTX-WP s/bag...and to the sequential mind -also to any past or present non-GTX
waterproof-breathable-laminate shell construction s/bag...be it Exped, Mountain Hardware, etc
