Since I was about to recommend this steal of a bag to my scouts' parents, I decided to spend a night in it last night. Finished up working really late and didn't feel like pitching a tent, so I laid down an Exped UL7 mat on our trampoline, then took it out of the sack and fluffed it up. I climbed into a pair of wool socks, a set of poly thermal bottoms and sweat pants, and a midweight top and wool beanie. Climbed into a Sea to Summit Reactor liner (claims to lower a bag's comfort zone by 10 to 20 degrees; I'd say more like 10) and then into the bag. Temps dropped to 33-35 degrees.
I was OK and there were a couple cold spots, but I survived. Not toasty though, especially not with this little amount of fill. I'd say this is a great lightweight summer bag, comfortable to 45 degrees, or as a really packable second bag for shoulder and winter trips.
Without the sack it weighs 1lb 7oz. Trimming or removing the enormous drawstring could shave another ounce or so.
It does smell like you'd imagine a large building with thousands of ducks would smell. I'm thinking the bag's manufacturer didn't bother with a cleanliness clause in the contract with their down supplier. Or is this how all duck down smells? Some folks may have trouble with allergic response to this down and should try it out before relying on it for an extended trip.