I bought the jacket for my son. I was unsure about size because I know that Eddie Bauer runs a bit large but I'm glad I decided to go with a medium, which fit him perfectly. The jacket is great for when the weather turns a bit cool but not cold enough for winter gear, OR for intense activity in cold weather. I would guess it would be great for cold weather runs for example. I'm not wearing it myself but it seems it's doing it's job!