As some other reviewers have alluded to, this does run a little bit small. It definitely doesn't fit me the way to looks on the model!! But I don't like baggy clothing that will get caught in stuff so I'm ok with it but if you don't like it to be form-fitting or you want to wear layers beneath, I recommend ordering up a size.
I'm 5'8" and 170lb (more bottom heavy, very athletic chest/arms, no boobs) and ordered a Medium which was based on bust measurements. Compared to the flannel work shirt I ordered (which was perfect) the sweatshirt was snug everywhere.
High quality construction, nice feel to the material and nice "look" without to many frills.