Are liquid-fuel stoves better than canister stoves for cold weather?

Yes, the consensus across mainstream gear sites and mountaineering communities is that white-gas and multi-fuel stoves keep pressure and BTU output in sub-freezing temperatures where isobutane canisters lose performance or stop working entirely. That's why expedition packing lists for places like Denali and the Himalayas overwhelmingly specify pump-pressurized liquid-fuel stoves.