I bought a new sleeping bag for the first time in about 10 years. After much research, I settled on an REI
Halo +10 down bag. I was wanting a 0-degree bag, but got talked into a +10. I've had a -30 degree down bag for over 15 years for winter camping, but had always stuck to synthetic filling for warmer trips. Why? Two reasons. First, I hike a lot of slot canyons, and if you get a down-filled bag wet, you are in a world of hurt. Second, if you've been sleeping in a bag for six or seven days and it has gotten funky, you can wash a synthetic bag in your home washing machine. Not so easy to do with down.
