Western Mountaineering Puma Super DL

This bag works really well for brutally cold conditions. I originally purchased this bag about 5 years ago, looking to replace a 5 degree North Face bag that wasn't cutting it for me in extreme cold. So far I've used this bag about twenty or thirty nights in temperatures ranging from 10F to -20F. In my unscientific analysis of the bag's quality, it appears to loft more than some -40F bags I've seen, and the bag appears very well made.

One of the coldest nights I can recall with this bag was camping in the Presidentials in NH on a -20F night with heavy winds. With the bag fully zipped I literally slept warm in just my midweight Capiliene top/lightweight bottoms and some Smartwool socks. I would feel safe taking this bag to at least -30F, and I imagine I would still find it comfortable in those temperatures (I consider myself an "average" sleeper... not too hot and not too cold).

On the rare nights where I've used this bag above 0 degrees F, I've found it to be too warm... In my mind it really is a specialized piece of equipment that you only bring out for certain trips. But, in its element it does a great job!

Bought this bag in college about 13 yrs ago; best money I've ever spent, and I've spent a lot of it ;) This bag is absolutely bullet-proof and warm as can be, plus it compresses to the size of a volleyball. I use mine in all manner of temperatures, even when sleeping indoors; just don't zip it up. At some point I felt like the loft was going down a bit, but I just used it this weekend and it's fluffy as ever. I can't imagine a better sleeping bag.

Some mentioned problems compressing the DryLoft version. Just zip it inside out before you stuff it; problem solved. Of course if you do that, don't drop it in the river ...

A great bag with immaculate build quality, a ton of loft, double draft tubes and a comfortable hood. Haven't exposed it to anything colder than -17 C but I'm confident that it'll keep me warm and cozy at -30 C.

If I had to do it all over again, I'd probably get the microfibre version instead of the Dryloft. Dryloft works great but it makes the bag harder to stuff - especially when your hands are freezing cold.

Not fully tested yet under very cold conditions, but at 15F....

Just roomy enough to be warm and comfortable. I can flop side to side without twisting the bag with me. Lining is very smooth but strong feeling. Pleanty of foot room for streaching feet and morning clothes. Draft tubes seal off zipper area leave no cold spots. Sinching the draft collar around the neck creates an oven in the bag. Hood is puffed with down to the point of being pillow like. At 15F I could not make use of most of the above features because it was just to hot. Real winter tests will be coming soon hopefully.