I have another Sanuk, that i use for mild weather. and it works just fine.  i like the fact that it is stylish and comfortable.  i read some reviews about how warm this one is.  it is warmer that the other one but not at close to zero weather like some people exagerated.  also the way you see its shape. it does not keep it.  i don't know if the lining is heavier that the outer shell, but it caves in and does not look pleasant.

Revision: It is keeping its form.  Very comfortable. Not as warm as some reviews, but cozy best. Still, glad I bought them.