Not a 20 degree bag! More like 10!
Love this bag. I am 6-2+ and about 210. Got the long and it has plenty of room. The only downside is that it is snug, this contributes to its great weight and I feel it makes the bag feel warmer because there is less bag to heat. The equivalent wider bag by WM is the Alpinlite Super. The extra length lets me gather up some extra bag around my hips and knees so that when I lay on my side there are no tight spots/cold spots. I have been to single digits on several occasions in CO or on the AT in just silkweights and a hat and have been very comfortable, tho I do sleep warm. The full length zipper helps to regulate temperature on warmer nights or to open it up all the way and use as a quilt. The draft collar works great. I expect many years out of this bag but when I buy another it will be WM. Again this bag is snug, so if your are claustrophobic or want alot of wiggle room go with the Alpinlite. I dont use a stuff sack for this either, it goes in a dry bag in the bottom of the pack to fill in nooks and crannies and the rest of my kit goes in on top. Great bag.