This is a pretty good jacket, especially since I got about $100 off the original price! So far it's really warm in about 25-40 degrees, but I haven't tested it in colder weather yet--but I suspect it will hold up pretty well. Like another reviewer, I'm also a preschool teacher and stand outside for about an hour a day, in addition to commuting, and I've been pretty warm so far without wearing a fleece underneath or anything.
A little about the size- I'm 5'2" and very thin and got the XS, and it fits pretty well. I was debating between that and the Small (which I've gotten in other jackets), but I'm definitely glad I went with the XS. I think it runs pretty true to size. The jacket isn't TOO puffy in the body part, especially when you pull the elastic in the middle (nice touch!). However, I do feel the arms, especially the upper arms, are a little puffier than I've seen on other jackets, especially for someone thin like me.. and I did get the smallest size.
Another really small thing I don't like is the white zipper pulls on the main zipper and pockets on the brown jacket. It just stands out a lot.. but it's not that big of a deal.
Overall, I'm happy with my purchase so far! I really needed a warm jacket as we head into the winter months in Boston, and I think I've found a warm and durable coat that will last a long time.