I did the same thing as the other reviewer, but I'm 6', 160. The large is for everyday wear and riding. The medium is for wearing with my slacks and a polo when I'm traversing double-grey office hallways.
I love this shell. It fits about like a hoodie and has front pockets, arm pocket, tune pocket... The bonded fleece liner is really nice, and the 10k exotex is supple and smooth. I expected to use it more as a spring jacket, but it'll go nicely with a bit of layering on the cold days.