The test team at ProLite Gear really liked the Rab Spark lightweight rain jacket. They felt it had the best fabric of all the jackets tested, and it was the only jacket that used fabric that had a 2 way mechanical stretch. The jacket had an excellent 3 way adjustable hood with a wire in the brim, which allows the brim to be shaped the way you like it. It also was the only jacket to use Napoleon Pockets, which keep the pockets out of the way of climbing harnesses and backpack waist belts. The only negative was that the jacket was the heaviest of the bunch at 10.2 ounces(288 grams) for a size large.
View the article here: Best Lightweight Rain Jacket Reviews.