Very soft and comfy against my feet, and have definitely been kept warm. The zipper feels a little flimsy however, and gets stuck unless you hold an edge in just the right way, so I'm a little concerned about that durability. Perhaps they're just not fully broken in yet, but the stiff sole keeps the rest of the boot from flexing and it rubs against the back of my heel a bit since it doesn't follow my foot too well, but I'm hoping that softens up as I wear them more.