The shirt has a flattering fit. I think this is the first flannel that I can positively say is truly a relaxed, fitted women's shirt. It is wonderfully heavy for cooler weather. It keeps wind out well and is not overly warm for fieldwork. It's so versatile; I love it. I have an athletic build, am 5'3", weigh 120lbs, the xs fit perfect.
This shirt is not meant for women with longer arms! I purchased a few of these shirts thinking that was how the shirt was meant to be but it drove me nuts. Also, when you wash them, the sleeves will get even shorter. Even if you hang dry. For reference I am 5' 6" 125lbs and wore a small. I tried to go up a size but the shirt was wider and the sleeves were still short!
Normally I wear a small, but I purchased an extra small so so that it would still be fitted enough. This flannel is truly a flannel and not a the light weight shirt that looks like a "flannel" so it's perfect for those crisp fall days when you need a little extra warmth. I like that it has great range of movement in the arms and really does stretch well.