egui is nice for internal tools, and for quickly creating UIs for games and such, but I don't think I'd ever release a consumer-facing app with it. It has too many quirks compared to a more "native" UI that it can be quite awkward to use interfaces made with it. I'm talking about things like inertial scrolling, text selection, window resizing, etc.

It's certainly nice to work with from a developer's perspective, what could be easier than

    if ui.button("Say hello").clicked() {
        println!("Hello!");
    ]

?

But it's quite a pain to style if you're particular about typography and pixel-perfect layouts. Between styling an egui app and styling something with CSS (or some flexbox/grid system), I'll take CSS every time.

Still looking forward to how Xilem turns out, and what people build on top of that.