I recently got this bag for backpacking after doing a lot of research. My previous experience has been car camping at best, and most of my upbringing was road tripping in an RV. Not exactly braving the elements.
I used this bag over Thanksgiving weekend while camping in northern California's redwood forests. It was cold and wet throughout the night, but the bag worked well! Full disclosure: I also had a silk liner, which helps hold in warmth.
I love the puffiness of the bag, and there is enough room for me to turn and roll throughout the night (I'm a size sleeper). If I got chilly, I pulled on the mummy strings and was soon toasty again.
I'm 5'5" and got the regular length, which is just about right. If you're taller, you might want the "long" size.
This review was written in the old system and had content requirements that are different than reviews written today.