The Amazfit GTS watch has an amazing display; very high resolution and very bright. This is the best feature of the watch. It also has very good battery life; even with the display set to its maximum brightness and 12 second On-time and measuring my heart rate every 5 minutes, it still lasts and lasts. I haven't made any exact measurements of the battery life but I am very happy with it. The heart rate sensor seems a bit so-so. It is slow to get a reading and when set to do regular readings it sometimes misses getting a reading at all (you can see that on the graph of heart rate). Also the weather data is suspect. Firstly I cannot set it to show my local weather and the data that it does show (for a nearby town) does not agree with the data for that town taken from other sources. Disappointing.
The watch is very comfortable to wear, being very thin and very light. The Countdown timer function, which I use a lot, is very well implemented on this watch.
Overall I am a little disappointed but there is still plenty to like about this watch.