To plus-1 this: if you've ever been chilly in a winter jacket, it's the jacket's fault. Actually-good winter wear can easily keep your body comfortable in wind and literally-Arctic temperatures. And puffiness has next to nothing to do with warmth at normal temperatures, it's mostly just fashion (one which says "I have no idea what I'm doing" imo) - the warmest stuff isn't much thicker than stuff you can find anywhere, though it is generally stiffer.

It's extremely worth over-insulating by default because it's so easy to fix: unzip a little. An extra $50-100 on something that'll last a decade is an excellent cost/benefit ratio, and if you're somewhere that gets truly cold it can literally be a safety issue.