Warm, Dry, Compressible
I bought these boots for a winter/spring yurt trip, and was thrilled with them. I have terrible circulation to my feet, and they are always cold. These booties were light and took up extremely little space in my pack. They were quite warm, and stayed dry in the damp spring snow. I walked around in them outside more than I thought I should have, and they seemed to stay perfectly dry. They also have a decent amount of grip in the sole, and was a bit tougher than others I've seen. There's also a good amount of insulation in the snow so that walking in snow you don't feel the cold in the soles of your feet.
Getting the right size was an issue for me. I'm a women's 8.5 to 9 shoe, and ended up being an XS in these. (According to the sizing chart, I should be a Medium, which was huge, and even the Small was too big.)