OK, The jacket is great for mountain biking. I had bought a couple of other jackets before this one and started to sweat almost immediately to then realize that I felt cold and clammy. YUCK! Spending the extra money on the Featherweight is definitely worth it. I didn't sweat any more than normal with this jacket and when I start to get a little warm, I just unzip it partly and feel great. Best jacket I've owned so far!

This shell is PERFECT for biking and running. It's extremely lightweight, breathable, and full of stretch. It's an excellent windblock and sheds water in a drizzle. It's cut to fall at the hip so it's not bulky. There's a drawstring at the bottom, and the sleeves have an extra insert with thumb hole to cover your hands. The neck has a soft lining and there's a windflap on the main zipper. All the zippers are high quality. I really like the flat seams too. I like mine so much that I'm buying a 2nd one -- it's the most comfortable, functional, attractive aerobic jacket I've ever owned and I've owned many of them!