Goran S. wrote a review of MontBell Super Spiral Hugger #1 Sleeping Bag: 15 Degree Down on February 19, 2013
Familiarity: I've put it through the wringer
Bought a pair of these for wife and I. We used them in everything from 10 (long johns and a shirt) to 70 F (of course, unzipped) and they worked great. We got them with opposite zippers, so if needed you could zip them together and probably go down to 0. Lots of room for spinners.