Today, it was a chilly 22F in the morning, so I decided to give the jacket a serious test. I put on a tee, zipped up the coat and went out the door. After about 10 minutes walking I began to feel the cold (mind you the wind chill made it feel about 14F). Overall, A+ performance!
Down is extremely warm for its weight. It's only drawbacks are that it looses its insulating ability when it gets wet and it requires special washing treatment. But if you've bought down to wear in subfreezing temps, then moisture won't be a problem, and jackets seldom need to be washed. Should work great for you.