Yes, replaced few rich and reasonably complex UI components in admin interface that were previously developed in Adobe Flash (developed in the times when html wasn't as expressive for more visual/interactive UIs). The end users did not notice any difference.

The language is pure joy to work with. No issues with "deeply nested components", just use a function to render a "component", add data needed for the rendering as a function parameter, handle the events emitted from the "component" in the update-function.