the snowy Down was the warmest, but it was also the most expensive. The Northern Trek cost less than the snowy Down, but it was just as expensive as the Ultra Comfort. The Ultra Comfort was warmer than the Northern Trek. Finally, the Ultra Comfort was lighter than the other sleeping bags, so it was easier to carry. I decided not to get the Northern Trek for camping outside. It wasn't as warm as the other sleeping bags. But we were having a mild winter, so I didn'