I am surprised to hear about the poor quality military sleeping bags you experienced. Again, going back to "starving student times (1950s)" one of the better mil surp items I used was an Army "mountain" sleeping bag, filled with a down/feathers mix. It was heavy and a tad bulky, but I know I slept out in a snow cave at -30F rather comfortably. Must have been Korean police action vintage....

If it hadn't been for mil surp, I would never have been able to venture beyond the pavement. I retain fond memories of that bag.