For the price, you cannot beat this jacket. It's incredibly light and very warm. I've worn it for short periods down into the mid-20s so far with just a t-shirt underneath, and it's performed perfectly. With my Patagonia Lightweight R4 underneath, I'm sure it could go below zero no problem. And best of all, it packs down super small (great for travel, skiing, etc.). I'm 5'9" 150lbs and the Medium fits very well, although it is a tiny bit long in the back for my taste. I got the grey with the green accents and it looks great too.