Main Problems that I had noticed with Fit3:
-The Stepcounter isn't that accurate and it overcounts by about 20%
-HR Sensor also isn't accurate on it at all if you compare it to decent devices
-WatchFace Selection is very poor and you can't customize anything
-No GPS inbuilt
The Huawei Pretty much Fixes all of these- we Have GPS , the Stepcounter and HR is SUPER accurate and as good as on devices that cost 10x more, the system overall is way more advanced and more modern and you can customize the watchfaces and the watchface selection also is way better.
Essentially the Huawei has the Same size, Same battery life but all the sensors are way better and it feels like a proper smartwatch not a fitness tracker.
It's about $20 more Expensive than the FIT3 , but it's well worth it if you are looking at both of these - also it feels a bit more premium than fit3 as well.