How warm is this sleeping bag?
Not very. I would say that it is good for indoors, or at least in tents and that at a pretty warm temperature. What it is good for mainly is that it packs down to a really convenient size, and it is very light.
Appropriately warm for its rating. I use it for hut trips in the Colorado mountains at 11,000 feet where the cabin is heated by fire but the sleeping rooms can be isolated and chilly, especially in the wee hours when the fire is out. I accept the fact that for the smaller weight and packing size, I might have to wear some more clothing to bed. The compromise works for me.
It is really like a blanket. I got it to take to India last winter. It worked just fine for that. It is light and small which is also why I got it. I'm comfortable using it in weather just below 60--say 55. I'd have to have a lot of clothes on for 45 to be acceptable.
Good summer bag..... Ok for 50 or warmer.