When tent camping, I've been sleeping with a pair of down booties each fall for the past 10+ years...excellent. They were gifted to me and don't have a tag. Nothing fancy, no exterior sole...essentially they're down socks. I have an excellent WM bag (Badger), but wearing the down booties/socks over my light weight liner socks works great for me. I typically have two pairs of wool socks hanging on a line in my tent, which I rotate between each day.
Side-note...I did a personal field-test of the new KUIU down booties during an 11-day remote tent hunt in September this year. They were a great addition to my line-up. I wore them as a welcomed brief break option for my feet when wearing knee-high insulated boots all day, e.g., sitting and glassing, sitting in the tipi, etc. They were really great for me and worth the price! That said, they would be way too much for me to wear in my bag at night.