I wanted a lightweight jacket/shell for backcountry snowboarding that I could also take to the resort. Had also looked at the Sphene which is lighter but was missing some key features for my purposes - specifically the front pockets were too small to fit skins. The Rush has been great on my trips so far, it's light and easy to pack when needed but provides great protection.
I sized down from the Sphene and from what I normally wear, getting a Small so it fit closer. Still provides room for a light down jacket underneath and gives me the closer fit I wanted. I am 5'11" 155 lbs.
This review was written in the old system and had content requirements that are different than reviews written today.