A good quality sleeping bag is very important. Don't skimp on it you will regret it. I would go with a down bag they are warm and light but cost more. Any sleeping bag over time collects oils from your boddy and degraids the insulation. To revamp the life in a bag wash it. Also (this is important) the sleeping bag will only keep you warm if you are off of the ground. When it is really cold out I use 2 sleeping pads. A closed cell foam pad and then a thermarest air mat. The foam keeps you off of the ground and then if you stick the air mat in your bag the air will heat up and keep you warmer. Also you will be more comfortable. I am a Mountaineering guide and have been using feathered friends sleeping bags for years. I have used there 0 degree bag in Alaska, CO and the Alps and have never had any issues. As a matter of fact I have had the same bag for 6 years. Well worth the price tag.