My first job was as a Silverlight developer. I used to complain all the time about XAML, and as a huge React fanboy, its been lurking in the back of my mind. Why would I like JSX but not XAML? Especially since early Silverlight projects used 'code-behind', which is essentially just a c# file that is paired with each component. How is this different than React? At all?

I think the biggest difference is that XAML was really terrible to work with in part because of proprietary components and the massive tooling around it. I remember I'd have to use Blend whenever I wanted to change how something looked. And then there wasn't a great application structure that moved along with it. I pushed really hard for us to switch from code-behind to MVVM for our application architecture. It worked great, and made everything much easier, though it was really abstract and styling was difficult still. But that was my first job--maybe if I went back it would seem trivial.

I don't know if this applies to XAML, but once you start thinking of React in a component architecture model (knowing JS helps too!), the declarative style makes so much sense.