I just had a chance to try out my bag where the low was about 30 degrees and it completely exceeded expectations. Certainly warm enough at those temps with just a base layer and socks and I believe easily down to 20 or so before more layers would be needed. The extra room provided by the spoon shape is awesome. I did consider a Strato Loft as I was concerned the Nocturne would still be too tight around the elbows but the extra weight, lack of long option and higher temp rating dissuaded me and I'm glad they did. The Nocturne has plenty of space to allow free movement. I'm 6'3", 250 lbs. and a side sleeper and was easily able to turn side to side within the bag. The extra comforter-like flap at the head opening is terrific and really helped keep a good seal around my neck. I will never go back to a traditional mummy style bag after experiencing this design. The quality of materials and construction is top notch as one would expect from Nemo. The zipper pulls easily and the lining is very soft. If you struggle with the confines of a mummy, this bag is definitely worth a look.
This review was written in the old system and had content requirements that are different than reviews written today.