Yup, I used it on a client application the first time I used it and it worked very well. The project was finished a while ago, and Nativescript has made leaps and bounds in that time, it's even better today.

I used Nativescript-Vue[0] which has since been brought under the nativescript umbrella fully, and it was a great experience. Vue is drastically less complex than React and that translated to very easy app building.

I don't build mobile apps (I think the market is somewhat saturated), but if I had to, I wouldn't even consider Flutter these days (I've built a small app in that as well), or building natively (who wants to be an "android developer" these days if you don't want to specialize in it?) -- Nativescript all the way.

There's also stuff like svelte-native[1] -- Nativescript is a better platform to build on than React Native. Props to the React Native team for being the first to have the idea (same goes with the component-driven design of react itself, though arguably backbone/marionette views were first), but Nativescript is a much more flexible and easy to use solution.

[0]: https://nativescript-vue.org/

[1]: https://svelte-native.technology/