I am working on 3 Flutter Applications & 2 of them are currently in production. On average we receive 1 major bottleneck a month, which gets resolved with 3rd Party fixes. Happy to help if you are stuck on any issue with Flutter. Our background is native application development, so far this is the best Cross-Platform Development toolkit available. Phonegap, Ionic & others are web wrappers. PLEASE let Flutter grow!
React Native isn't a web wrapper. It uses a Javascript engine to render native iOS/Android components (unlike Flutter, which doesn't use native components, and instead renders everything from scratch).
Although React Native shows Native elements, they vary slightly across different; devices, platforms, OS's etc.. this can create many weird edge cases, which makes it unreliable in some cases.