First of all, for the size. My son is wearing a medium right now, so I read the reviews and purchased a large of this sweatshirt. Still not good enough. If you do decide to buy this, even after reading the not great reviews, I would suggest you buy two sizes above your typical size.
Second, for the material, it is very poor quality. The images almost make it seem that the material is a bit thicker than it is, but it is incredibly thin. Overall, I was disappointed by this purchase on a couple of levels.