Wore for a week while hiking the Alps. Definitely waterproof in light rain, although we weren't in any heavy rain. It is very lightweight and packs really small, so I never thought twice about keeping it my backpack, even when rain wasn't expected. It is a little oversized, but that is what I wanted so that I could wear other layers (lightweight down jacket) underneath. I have a heavier Gore tex rain jacket, but suspect it won't get used much now.
This review was written in the old system and had content requirements that are different than reviews written today.