After years of freezing my buns in high alpine camps I was pleased to finally get a good quality zero degree bag. I'd been wanting to try one of Montbell's Down Hugger 800 bags for a long time since I'm an "active" sleeper.
Given that we had the summer of no summer in the Pacific Northwest I also got a lot of opportunities to use a zero degree bag, even though it arrived in June. I've used it both as a back country bag and in the front country and overall been very pleased with it.
The Down Hugger is sewn with several "tricks" using elasticized thread, bias cut fabric, and seam line alignment that make it "stretchy." The bag moves with you while you sleep eliminating drafts. The main reason I could never go the way of the quilt is that I'd never get any sleep. I toss and turn and roll around constantly. The Down Hugger truly does stay with me, keeping me warm, and yet I don't wake up panicked in the middle of the night because I'm in the mummy hood backward and can't breathe. (true story, this happened all the time in my old mummy bag)
The hood of the Down Hugger has a nice neck baffle that provides additional draft blocking. I like that it adjusts independently from the hood cinch so that I can vent the bag differently depending on conditions.
At 2 lbs, 14 oz it is the heaviest sleeping bag I've ever owned, but on the nights I'm dug into the snow at 7,000 ft or more I'm perfectly content to have carried it up there.
The only drawback to this bag is that they do not offer a "short" or female specific fit. I swim in the regular and as such, it doesn't keep me as warm as a 0 degree bag with less internal airspace would.
I am a Montbell Athlete and receive my gear at no cost.