After looking at some great pics in the thread "what are you wearing" I am considering buying a fleece jacket. I love the look of the B3 and the Irvin however winter temps here rarely stay below 15F (-9C) for very long. Therefore I'm thinking something like a D1 or B6 may be more appropriate. These jackets look very similar to my untrained eye. So my question: Can some of you who have owned these jackets compare the two for me? How do they differ in fit? Is the fleece similar? Which do you prefer and why? Thanks for your thoughts.