Poor user interface, proprietary, and super bad manual
These days most thermostats are relatively intuitive but this one is not.
Okay so that means you gotta use the manual. No dice. The manual doesn't appear to be written by someone who understands the device well enough to explain it in English. For example, there are two sets of instructions for " To set the Daily ON, OFF and ON/OFF TIMER" and they are completely different. And neither achieves the result alone nor together.
Okay so that means maybe I should buy an after market thermostat like a Nest. No dice. Not compatible.