In reply to Merlin:
I checked one out in Boulder, CO a few weeks back, side-by-side with the older Fission parka. The Dually seems 'bigger', longer and much lighter, but not as good quality. Puffier than the Fission. It's a very simple design, no frills, not as fitted as the Fission, and I'd have to say it generally looks and feels 'cheaper', but it costs similar. I love Arcteryx and have several garments, but I wasn't impressed. I like clean, simple design, or 'invisible' design, and though the Dually looks clean and simple it didn't seem to have that more subtle quality that Arc traditionally has. I think currently the Patagonia DAS is a better garment for same use.
D