If you go to the Gore website they have an explanation about how Goretex works and about breathability of Gore fabrics. Really strenuous exercise can produce enough moisture to overwhelm the ability of the fabric to pass water vapor molecules through it. Then you get wet from the inside.

I have one of the Gore Windstopper neon green visibility active shell jackets. It really works to stop wind from wicking heat away from you. If you ride in a low humidity environment when you do get even a little damp the wind can really be chilling. I use wool sweaters of various thicknesses underneath it as it cools down in winter. I bought mine at a garage sale for a couple of bucks so I have no reason to complain about anything. It was a good buy.