I had been focused on using a layering system based on a MontBell down jacket and inner layers for similar temperatures until I tried the MEC Reflex jacket. Not only is this jacket quite reasonably priced, and built to match the rigors of backpacking, it is also a portable furnace. I'm preparing for a trip where I expect temperatures to regularly be near 0 F or below in the evenings and nights. I had considered using a North Face bag which has never left me cold in 30 or so years of use, but which is bulky and somewhat heavy. With the MEC jacket, I feel comfortable using my Marmut Helium membraine instead, and planning to wear the jacket to bed. Having the jacket will also make getting up in the night MUCH easier. The MEC sewing is just as good as my FF products, in my opinion, and the materials are well thought out. There are 16 ounces of 800 fill down in the large, and 17 ounces in the extra large jacket. The down side is that my large weighs 28.0 oz. Hoewever, for really cold conditions, I'll take the weight for the comfort. I'm now able to keep from going right into my sleeping bag in the evening to keep warm. I sleep quite cold, and generally find that a sleeping bag keeps me comfortable only to a bit above the women's rated comfort level. For instance, my Helium only keeps me comfortable to about 28 F, and this is with a medium weight base layer, and balaclava. However, I am experimenting with using the MEC Reflex combined with FF volant pants, FF down booties and Nunatak balaclava, OR mittens as a sleep system without a sleeping bag down to the mid-20s or 30's. While the individual clothing items might be heavier, I think the lack of sleeping bag might make for a quite interesting shoulder season night. Anyway, if you want lots of warmth, give this jacket a look.