Nathalie C.wrote a review of Western Mountaineering UltraLite Sleeping Bag: 20 Degree Down on September 29, 2015
Familiarity: I've used it once or twice and have initial impressions
I'll start by saying I run very very cold. I was using a 3.7 lb. zero deg bag year round (except for hot desert camping) for the last 7 yrs and I have no problem sacrificing weight for comfort. I was concerned with the continuous baffles on this bag and losing the heat underneath me since I toss and turn a lot but as it turned out it was never an issue. I did a 5 night 6 day Sierra trip at the beginning of August (warm for some, cold for me) and would normally take the zero but I was on a mission to drop weight so after reading the incredible reviews I bit the bullet and spent some money on this bag and it's one of the best purchases I've ever made.
It's so light, it definitely helped me get to my goal pack weight and it packs so small it's hard to believe how warm it kept me and how well it lofts. I slept with a light base pant and shirt, no socks and when we had a couple of really clear, cool and very windy nights and I got chilled, I tightened the collar a bit and like magic the heat was instantaneous. The pull ties were easy to work with on the hood and around the neck and I was able to find the perfect combo. Another plus is my zero zipper ALWAYS snags, every time, and this one didn't snag once, even from an opposite pull across my back.
This bag blew me away. Based on the reviews I knew it was a good bag but I didn’t expect it to perform as well as it did for me and I see many years of use in it's future. I would highly recommend it to anyone looking for warmth and to save weight.