I'll jump to flutter once they have a convincing media player / recorder native component as well as a google map equivalent. If this has good performance on both iOS and android, with features comparable to native ones, then i don't see what can stop them.

Unless Apple starts implementing its own cross-platform sdk in swift... But judging by the slow pace at which swift is moving (compared to its "worl domination" ambitions, that is), i don't think it'll happen anytime soon.

World domination in Swift's context means iDevices OSes, outside it will be just like Objective-C has ever been.

The Google maps plugin is in active development. There was just a stub merged into flutter/plugins on GitHub

It's open source. Even if they abandon it, it doesn't go away. If it turns out to be good tech, others will maintain it.

That's the #1 reason that I don't currently consider it in the same class as React Native. Once Google showcases how they're using it in business critical apps, then I think I'll have the confidence it won't be another project that gets the axe.

Flutter (along with Dart) is used for AdWords, which is Google's mission-critical, billion-dollar business. It doesn't get much bigger than that.

They use it for the AdWords mobile app. That's pretty much as business critical as it gets for Google.