Hi manguadai,Windstopper is NOT waterproof like eVent. It is "highly water resistant" as Gore will tell you, but it won't shed off a downpour. Rather, it is totally windproof. Windstopper is highly breatheable though, so you won't end up soaking in your own perspiration when wearing this jacket. eVent is also breatheable, arguably moreso.-------------------------------------------------A little bit more technical info. Neither Event or Gore Windstopper are what the industry calls 'air permeable.' There is a difference between air permeable and breathable. Both Event and Windstopper are ePTFE laminates and they are considered breathable as water vapor passes out of the garment but not back in due to their inherent waterproof-ness. In an air permeable garment water vapor, water, and wind for that matter passes into the jacket and out of the jacket or garment (think non-laminated softshell) due to the lack of that water proof or wind proof laminate. Also, depending how you build the garment, what fabrics you use, play a huge roll in determining breathability. It is not true to say Event is more breathable than Windstopper. Windstopper is a thinner laminate and is usually constructed into a garment and coupled with fabrics in a way as to encourage maximum breathability and not waterproof-ness. Event is usually placed in a garment with waterproof-ness being the main concern and breathability coming a close second. Also, it is true that Gore is more durable... but, that is another story. Hope this info helps!