They seem similar in intent and application, however Flutter skips the Javascript-to-native bridge and instead appears to compile to native code for the targeted platform directly, making it faster. In practice, React Native still _feels_ native because it is native and most devices are fast enough for most applications, but the Javascript that operates the native components has a performance penalty due to the bridge between javascript and native.

Dart still has a huge hill to climb for mindshare. The staggering amount of community and documentation around react makes it difficult to carve out a competing solution without the same size of community to write documentation, examples, and answer questions on Stack Overflow.