ID Hot Socks v. Sierra Designs Down Mutts/Booties

Hi all,

I was curious if anyone could speak to these? I'm looking through some of the options at ProLite and would like to pick something up for this winter for foot warmth while sleeping but also for light walking around camp in the evening.
Anyone have any experience with IDs Hot Socks or Sierra Designs Booties/Mutts? My use would be for insulation from cold weather and not for tramping through snow (though snow could always show up whether I wanted it to or not).
I'd love to hear some opinions. Thanks!