> On the other hand, my simple Honeywell thermostats do wonderfully because I can program them to my actual schedule and only need to adjust things twice a year. Sure, it's probably not as efficient as a dynamic algorithm, but I'd rather to do this than worry about waking up freezing in the middle of the night, or worse, having my condenser unit fried by an over-eager thermostat by starting/stopping it constantly.

That's my big problem with Nest. A basic programmable thermostat with manual override and a delayed blower feature is probably an 85% solution. Machine learning on top of that, for a single-family residence, is ridiculous overkill for very little gain.