Easy setup and worry free scheduling. I was having difficulty getting both of my ac units to equally cool off my house, one would run all the time causing the other not to run leaving some rooms too warm. I used 2 temp sensors along with this thermostat and the t10 for my other unit and now the whole house is comfortable
Frustrated with wireless connection problems. I have a T10 and it connected with ease but T9 will not connect to my main SSID. I only am able to connect to my guest SSID due to issues with 5GHz vs 2.4.
Two smarts I love about my T9 are that when the screen goes blank it means the breaker switch has flipped off, and secondly, I love the system's ability to average out temperature readings from dispersed sensors and change priorities as the sun moves over the house.
The T9, with additional room sensors, is a great thermostat. I think the only thing I can really say that is wrong with it is that the dimmest night setting is still far too bright. As a result, the screen is either too bright or needs to be set to the 0%/off setting. Therefore, I would not recommend this unit to be located in a bedroom. If it wasn't for this one issue, I would have given a 5 star rating.
The guided setup is easy to use and allows for ample versatility. You are able to adjust the temperature based on the main unit, or an average of multiple zones, for ANY period(s) in the schedule. You are also able to have the thermostat utilize the motion sensor, in a given zone, for priority to be given to the zone(s) sensing movement.
All in all, I am very happy with my choice of thermostats.