I've been using the Nuclei for a couple weeks now, and am pretty impressed by it thus far. The hood is a nice fit with no helmet, materials are very soft and reminiscent of how my last comfy down puffy felt (which is important as I use my jackets as a sleep layer often) and the arms are nice and long. This was my first Arcteryx purchase and am thoroughly impressed by the fit. I'm a slender/tall/athletic build and almost every garment I try is baggy in some spot or another. This jacket feels tailored to my physique. I will add though that if you have much extra weight, you might need to size up or consider a different jacket. I haven't had a chance to test it out in very low temps yet, but in the morning when it's still lower 50s I'm sweating in it, so I have no doubts with my merino long sleeve and this jacket that I'll be comfortable in all 3 season temps. My large came in at 11oz.
The price seemed reasonable on this jacket too, considering what the brand historically gets away with charging.