I have the Ex Light Down Jacket and I love it. It has a very aggressive weight to warmth ratio. It doesn't have any extra features so if you need those, go for the UL Down Inner Jacket instead.
I disagree that a parka is more versatile than a jacket and beanie. A jacket and beanie is better for temperature regulation, in case you want to wear only the beanie without the jacket, which you cannot do with a parka.
Another good reason I prefer a jacket and beanie:
When it gets cold enough where you need to wear your down clothing to bed at night, it is better to lay them on top of you rather than wear them. This is the same concept as a quilt, so that you are not crushing any down underneath you and rendering it useless for insulation purposes. If you use this method with a parka, you no longer have anything to cover you head, whereas if you were using a jacket and beanie, you still have the beanie to keep your head warm. In this way, you are able to take full advantage of every single ounce of down you have in your pack.