I am trying to find the perfect temperature sensor with the help of the best buy guide from Homey. 
I wanted to share some practical experiences. Maybe somebody is interested.
TLDR (November 22, 2024)
I like the Aqara sensor better. Smaller, less bulky, with a slightly better update cycle of the measurement, but needs a pretty good Zigbee network.
Size Comparison
You can see that the Third Reality sensor is significantly larger. Compared to the Aqara almost bulky. This is due to the fact that the Third Reality sensor has two AAA batteries wheras Aqara is using one CR2320. I do not have any experiencies regarding the battery life. I hope for both sensors for a battery life of more than a year, but let’s see.
Aqara Temperature and Humidity Sensor
Price: 24,99 € on Amazon
Capabilities: Temperature, Humidity, Pressure
Performance:
I have the three Aqara temperature sensors at different places. One was at the beginning quite unreliable, but that changed after I installed two more Zigbee router devices. An Ikea contact sensor, even 1m farer away from the nearest router, did not had performance issues. That leads me to the conclusion that you should ensure to have a good quality Zigbee network to get reliable measurements from the Aqara device. Now, the temperature sensors seems to deliver a new measurement every time the value is changing, but not completely reliable. Opening a window, and you can feel the temperature difference, will not always lead to a new measurement. Sometimes it takes 5-10 minutes to update. Pressing the small button on the to delivers a new measurement right away, with the new, changed temperature.
Aqara Advanced Settings:
You can see that the Aqara sensor has options to set an offset for all three values. The reporting accuracy can be set to one or two decimal numbers. I leave it to you if you trust the sensor to deliver such an accuracy.
Third Reality Temperature Sensor Lite
Price: 17,99 € on Amazon
Capabilities: Temperature, Humidity
Performance:
No long term experiences yet.
Third Reality Advanced Settings:
There are none.
This is a comparison of the measurements. Left is the Aqara, right the Third Reality sensor. The sensors are right next to each other. Screenshot taken after 30 min. Last update from the Third Reality sensor was 25 min ago, last reading from the Aqara sensor was 3 min ago.
Insights graph (Aqara yellow, Third Reality blue) - (updated on November, 23, 2024)
The measurements from the Aqara sensor seem to be more smooth. If this can be translated to “more regular” or if some kind of algorithm is averaging the temperature measurements more nicely I cannot say.
