Its supposed to outperform anything on the planet when it comes to waterproof /breatheable. All I have to go on is what I experienced Wednesday and what my gear head son tells me. My experience was a surprise in that although it was pretty warm I didn't get soaked with sweat and stayed protected from the rain. My lower half got a bit wet but thats because I was not wearing my good W/B rainpants, just some cheapie things I have had for several years and they suck in moderate to heavy rain. The water just rolls off the e-vent fabric, now I don't know if its a surface treatment and will have to be washed with techwash after a while or not. I'll need to find out