alt Hacker NewsRunning open-source firmware someone's hacking on (which gets little to no testing) on a gas appliance that can burn your house down is probably not the best idea.
If you are paranoid about Nest being evil maybe stick to one of those Honeywell round hockey-puck things with the mercury inside.
Or use a Z-Wave/Zigbee thermostat from a reputable vendor (there aren't many) and control it from a gateway of your choice.
This is for people who have already bought a nest and got burnt by the deprecation of their online services. Of course they could get another thermostat but then that'd just be more stuff for the landfills.