"Learn once, write everywhere". Can't speak about performance comparison vs using Qt/.NET/whatever but the whole idea about React Native is that today, you can write a native app for iOS, tvOS, Android, web, macOS, Windows, and a few others, all using the same language and framework. You still have to understand platform specifics like UX guidelines but you use the same technology to build a fully customizable, and fully performant, native experience. It's sort of like using C++ but way more developer friendly.

The cons:

- an extra layer of abstraction

- need to write a plugin if you want to surface a native functionality to RN if it's not yet supported

- no visual UI editor like in native tools (Qt/VS), although you generally won't need it with React Native's code-first and instant refresh development workflow

- you need to be comfortable with React Native / JavaScript, obviously :-)

It's impossible to use native widgets with Qt. React Native for Windows will make it possible to write applications in the React style (PropTypes and automatic propagation of updates), but using native Windows widgets.

While Qt emulates something like WinForms quite well, I don't think it emulates WPF widgets at all, which I speculate this wraps.

Given that WPF is the primary GUI toolkit on Windows, the only reason to accept Qt, is if you're making something like a WinForms application that you need to run on all platforms.

Sounds like it will bring React apps a lot closer to their Windows underpinnings:

> Sometimes an app needs access to a platform API that React Native doesn't have a corresponding module for yet. Maybe you want to reuse some existing .NET code without having to reimplement it in JavaScript, or write some high performance, multi-threaded code for image processing, a database, or any number of advanced extensions.

> React Native was designed such that it is possible for you to write real native code and have access to the full power of the platform. This is a more advanced feature and we don't expect it to be part of the usual development process, however it is essential that it exists. If React Native doesn't support a native feature that you need, you should be able to build it yourself.

Source: https://github.com/microsoft/react-native-windows/blob/maste...

Qt's licensing for commercial products is something like $500/month/developer. For a small team of 6 developers, that's $36k in licensing a year. Unfortunately, you're not allowed to take existing Qt code and "port" it over to the commercial license -- you're required to start from scratch IIRC.