I will say fit on this (like everything) is dependent on personal fit preference, climate, and intended use. I normally wear large in street clothes and the large 240 fits me. For me I don’t like baggy and bulky clothes, so I don’t use the 240 as a huge outer layer where I can fit five layers underneath. I wear a base layer and then the 240 over it, and this works down to 40’s or 50’s (depending on if I’m sitting or moving) it’s enough. If it’s any colder or raining I’m putting something over it (puffy, rain jacket, etc) and it becomes a mid layer. If you want more than a base under it, go a size up from your normal clothes size. It doesn’t have a draw cord at the bottom, so if it’s too big and used as an outer layer it’s going to let a draft in potentially. It’s comfy, breathable, allows for good movement, quiet, and versatile; surprisingly it’s becoming a favorite. If you get the hooded version, the hood is pretty snug but has a benefit obviously. I could see where not having a hood on it would be good too (if you have three hooded layers on).