I am 5' 5" and wear a small in some ll bean items and a medium in others, typically when the item is described as "fitted". I ordered this jacket in a medium and it is a good fit. I love how light the jacket is and not at all bulky. I have worn it for walks in 20 degree weather and have stayed surprisingly warm.
I love this jacket! It is very lightweight and warm. It is perfect for driving, as it is not bulky. It gets cold in Maine, but I have never been cold wearing this jacket. IT is perfect for shoe shoeing and cross country skiing, where a normal down coat would be too bulky.
Living in Ontario, our winters are pretty nasty. -25, -30 some mornings. I usually hybernate in the winters because I'm cold when it is +20 out! I got this jacket for Christmas and I can honestly say, even with a t-shirt underneath, I can't believe how warm it is! When I took it out and felt how light it was.... I really doubted that it was going to keep ME warm. There have only been 3 times, while doing chores in sever wind, I needed a little extra. So, I just threw on my LLBean 650 down fill jacket OVER TOP and it wasn't even bulky!!! And then nothing could stop me. My partner wears his under his ski patrol jacket and on the weekend, it was -25 (even colder flying down the hills) and he said he was completely warm. Yes, the feathers are coming out as someone else mentioned, but I figure if it interfers with it's warmth, I will worry about it then. Sleeves fit MUCH better than the 650 fill jackets. No complaints here. As for the durability of the jacket as some have mentioned.... I wear mine in the barn with my horses, throwing up tack, throwing down hay, riding through the bush.... no problems yet! I love it and would seriously recommend it to anyone who detests the cold. Another wonderful LLBean product that I count on to keep this winter wimp warm!