I got this sweater , I'm 5'6 and I got a s/m and it fits great! The material is soft but not too thick it's a little long but it's nice if you want to wear leggings with . It's super comfy and great for chilly nights :)
I am usually a medium because I have broader shoulders and long arms and I ordered a s/m and the sleeves were too short and it was tight though the shoulders. It also was not really a sweatshirt, more of a long sleeved tshirt. But nice quality and texture.