Dr. Ann wrote a review of MontBell U.L. Super Spiral Hugger #0 Sleeping Bag: 0 Degree Down on October 6, 2013
Familiarity: I've used it once or twice and have initial impressions
Just bought this bag and "field tested" it at a High Sierra lake last night. It's a zero degree bag that would probably actually keep me warm down to zero. I'm used to layering up clothes in my sleeping bags because I sleep cold. Last night I was taking things off. It didn't get down to zero, but it probably hit fifteen. I also like all the space in it. I'm a small person (5'2" and 115 pounds), but most bags feel cramped. This one didn't. Granted, there's a bit of a weight penalty, but this bag weighs less than my -5 Marmot Aiguille and that bag is a "short."
Bottom line: It probably won't appeal to the minimalist crowd out there, but I love bag. I've had other clothing products made by MontBell. They've all held up exceptionally well, so I'm expecting this bag will also.