After trying on the regular First Light jacket in a large, I decided to order this in an XL. Definitely glad I ordered up a size, the length is at low hip, arms are long enough to have no gapping when worn with mittens/gloves, and the shoulder width lets me maintain full mobility.
This jacket has insulation on the front through the core, in the hood, across the shoulders and through the top of the arms ending about 6 inches from the wrist. For as light as the insulation feels, I was impressed when I was able to wear this as my outer layer in 22-degree weather over a fleece, and a wool base layer and stay comfortably warm while I made my first turns of the season. The power-stretch type knit on the back and underside of the sleeves is extremely soft, and stayed dry even as it began to snow.
Super impressed with this jacket, and I would definitely buy it again. I've even started wearing it instead of my down puffer when I run errands and schlep around campus.