This is an incredible lightweight, waterproof jacket.  It has just the right amount of features for an uber light, on the go, hi octane endeavor.  This jacket is impressively breathable while maintaining complete waterproofness (not sure if that's really a word).  This is my first experience with the Gore-tex Active Shell fabric and I must say that I am very impressed. The only only downside of this jacket is that it is extremely snug around the waist.  I do product testing for Gore-tex and I've tried numerous jackets over the years.  I've never seen a jacket this snug in the hips/waist.  I'm 6'0" and 180lb with a 32-33" waist.  I have a size Large and I can barely fit a fleece layer under this jacket because it is so snug in the hips and waist (arms and shoulders are perfect!).  With many brands I wear a medium, though I usually bump up to a large if the garment is classified as "athletic fit".  This jacket is definitely an "athletic fit".