Samuel, I already have 2 Montbell #5 UL Down Huggers, a Super Spiral from the USA and a Super Stretch from Japan. Unfortunately, they were purchased prior to the Fall 2012 season when the USA models became EN rated. Spec-wise, they seem to be UNDERFILLED by 2-3 ounces of down compared to the latest EN-rated models. Moreover, even the current EN-rated #3 UL SSDH has ~1oz less down than this Bacoo350. Despite the underfill, they are comfy bags to sleep in though.
Obviously, what is making these Snowpeak bags seem heavy is the 20D fabrics, with the gray top being WPB/PU coated.