The use of widgets saves a lot of time, leaving one to focus on connecting everything together. It's also easier to learn than React Native (for me at least).
The current downside for me has been the lack of maps (I'm aware of current efforts). I also hit a weird Firebase Messaging bug that leads to an infinite loop of the app opening itself [0].
I agree with the author regarding the strong Firebase push. The community doesn't yet seem large enough, so outside of wine of the Google supported plugins, it's sometimes a struggle.
I am building a second app in Flutter, using the new Material stuff that Google announced this year.