We use alcohol stoves for our sub zero trips. No moving parts is a good thing.
For really cold weather, guys should consider also bringing some rubber gloves for fueling. You can get some serious frostbite going by spilling alcohol on your skin at sub zero temps.
Also, never refill a recently burned stove, you cannot really top these off during the burn.... Also, be wary of tipping these over, many of the catstoves have such a small footprint, they overturn quite easily, spilling fuel and flames.