I like the Primus Omni-fuel (I've also used an XGK), because you have the inverted canister option along with liquid fuels. We've used this in the single digits to melt snow for a group of five, worked fine, and we didn't even bother to swap out the white gas jet for the canister jet, so it was burning a little lean on the canister gas.

It's quieter and more controllable and easier to light without a flareup than the XGK, but a skinnier fuel line so maybe a higher risk for a clog with bad fuel. I figure you could purge the line with a canister if it clogged on liquid fuel, but that's a guess/hope and not anything I've read or experienced.