Sub-kilo is my only down bag, and I like it fairly well, especially for what I paid for it (ended up being like 150 shipped). It was right on its stated weight, packs down to nothing, pretty good zipper, etc. Like I said, for the sale price, it's a great bag.

It's a smidge snug through the corners if you're broad shouldered, but it's fine for me (5' 10" 165).

As for the truth of the rating, I'd say it's overstated by 5-10 degrees. I've had it down to just below 30 and was starting to get a bit cool, but still comfortable enough to sleep. Another 5 degrees and I would have been getting uncomfortable. I wouldn't take it to 20 degrees without extra clothing, a liner, bivy sack, etc.

Good piece of gear for the price you can get them at right now. I'm considering grabbing another one and butchering it for a quilt...that's doubtful though.