Pretty impressed with this jacket. I've been using it around town in temps as low as single digits, with just a t-shirt underneath and it's warm. Also I've got about 6 days wearing it at the ski area in very cold temps as well as warm and wet and it's a solid outerpiece for skiing. All days I've just used a mid-weight base layer and I've been totally warm. I do think the OmniHeat technology works. it's noticeably warmer than any other synthetic puffy jackets I have and similar even to a big down parka I have. For the price it's a good deal. Use it for general around town or as your go-to puffy on the ski hill. I probably wouldn't use this for technical stuff like climbing or backcountry skiing because it's a little heavy and bulky.
I'm 6 feet tall, 158 lbs and the large fits me well.