tl;dr version is the topic above. Now the wall of text:

While looking for a wind/rain jacket to take to Australia/NZ last year, I got a discontinued REI jacket on clearance. It’s great in general, and it kept me warm and dry during some wet conditions we encountered on that trip and since then. About my only complaint is that it’s not at all breathable, despite its claims. In fact, just about every light jacket I’ve seen claims to be breathable. However, it seems hard to imagine a fabric that would consistently keep water out, keep wind out, and let sweat out as well.

Some questions:

1) What sci-fi nanotech magic makes this possible? What’s the science of making a fabric that actually offers all three of these features? Isn’t something that’s totally waterproof in one direction necessarily also waterproof in the other? Again, everyone has fun diagrams of rain bouncing off and sweat evaporating through the fabric, but how does this work, if it indeed works at all? This is more out of curiosity, as I don’t really care how it works as long as it does.

2) Is there any standardized rating system for breathability and waterproofness? A thread here mentioned the Stormtech XWB-1 which actually lists “Breathable: 5,000g/m2/24hr”, which is simultaneously great and pretty useless without the performance of competitors to compare against, and independent testing for verification.

3) Ok, there’s probably nothing as rigorous as the above. But we need some way of comparing manufacturer’s claims, because every manufacturer claims to be both waterproof and breathable. Is there anyone who does subjective comparisons between fabric types/weaves/coatings so people can make somewhat informed buying decisions? We need not only product reviews but comparative reviews and parallel testing to really see where different products shine.

4) Is price any metric of performance? I’ve seen Arcteryx light jackets that go for over $500. I imagine they’ve got to be better than my REI jacket, but how much of the 10x price difference is branding, and how much is actual engineering and design? Specifically, how much better are their fabrics/coatings?

I’m probably going to be looking for a mid-weight winter jacket for short outings in 20-50 degree weather in the next year or two, and I want to make an informed buying decision. I don’t mind spending more for quality, but then I expect actual quality, not just empty claims. I figure this perceived paradox between waterproofness and breathability is as good a place as any to start my research.

TIA!