I bought the phantom last October, and rode all winter. (I ride to work unless there is a blizzard on - then I drive my Jeep.)
The first thing I noticed was the jacket's performance in wind - I could ride 2 - 3 mph faster in the same wind. It was marvelous. Of course as it got colder I added layers. And I logged miles, time, temp, wind, clothing, and comfort. I added a base layer at 40 degrees, a Garneau long sleeved cold weather shirt at 30. I was comfortable down to 20 degrees. I was cool starting out, but in ten minutes was comfortable, and in fifteen was undoing zippers to vent the heat. Below 20 degrees, sadly, I substituted another coat.
I love the Phantom - and I'm starting my second winter with it.