At the risk of starting a flame war, I very much agree with Dale on this.
Especially if you are anything above average in metabolism when awake, there's not much point in having a double windshirt with a smidge of fragile down in between. In fact, its more like two windshirts perforated with a lot of stitching, leaking heat.
I guess it really depends on what conditions you are in, but unless its a really dry trip, I'd struggle to choose this myself. Certainly, the Plasma with extra stitching and arguably more fragile down is less of a good choice. Spring/Autumn in arid conditions would be great, if your camp behavior means you are up and out of your sleeping bag still after dark (more likely if you aren't solo). Otherwise you'd be much better off just carrying a single windshirt, and putting the weight saved into extra down in your quilt or sleeping bag.
Also, the Ex Light might also be slightly warmer as it might have less stitching overall. At the temperature ranges these jackets are useful, the two layers of 7 denier might provide just about as much warmth as the 40g of down if they weren't perforated.