I used the T9 to replace a Nest "smart" thermostat. My beef with the Nest was that it was "too" smart, and was forever messing with the temperature, not to mention being next to impossible to use manually. The T9 does a great job of keeping an even temperature in the house, particularly with the remote sensors, of which I have 3. It's great as a smart thermostat and is easy to use in manually when I choose too.
Easy install, intuitive interface and the only reason why I do not give the product 5 stars [☆☆☆☆☆] is because, I have only had the sensor(s) installed for 3 weeks...
Great design and interface (through app & thermostat). Wish it had proximately sensor for the room it was installed in instead of having to purchase another separate one.
Had no real issues getting the t-stat installed. Remotes were easy too, after getting the routine down. Instructions for connecting the remotes, while technically correct, need to have a little more detail. I found a youtube video that walked me through it, and found that I was overthinking it a bit.