After spending some time with the pullover, I'm impressed. Stoic has made an excellent down pullover for UL 3-season backpacking and the value from SAC is almost unheard of. The only bad thing I have to say about it is that the pertex quantum fabric is rather noisy (crinkles as you move) - noisier than the pertex quantum GL fabric used in some of my other jackets.
It's light - 182.9g or 6.45oz for my men's M - and noticeably warmer than my old patagonia nano-puff pullover (60g primaloft). The cuffs, hem cinch cord, and buttons seal in heat very well. As for fit, it's close to ideal. There isn't an excess of dead space in the jacket, although there is enough room for me to layer my arc'teryx atom LT vest underneath without bunching. The forearms are somewhat narrow (for me, at least - I have large forearms), so much more than a heavyweight baselayer or thin fleece would probably begin to compress the down in that section of the pullover. For fit reference, my measurements are 5'8", 160lbs, 38.5" chest, 32" waist, 33" arms, 15" neck.