From what I can find about it on Google, Sierra's statistics are bloated. The bag is 3lb 12oz; 4oz heavier then stated. The recommended maximum height is 6'6"
The bag uses 600 fill down, which is probably adequate. I have Marmot's Sawteeth, which was 3lb7oz, and goes to 15degrees. I would say that 15 degrees is on the edge of comfort in this bag.
The DWR finish makes this bag attractive. I have a summer bag (25 degrees) made by Kelty with this finish. It works well to keep the moisture down. I have used it as an external bag on -35 degree nights in Bushnell falls, the Marmot fits nicely inside.
I have been very happy with my Marmot. You must be comfortable in a tight fitting bag to enjoy this bag.
-percious
