I'm using egui to build an app with a mobile ui and I'm really enjoying it so far. The main reason I chose egui is because I need tight integration with wgpu and this is really seamless with egui.

In the process of building my app I have also created a couple of crates for egui that add drag and drop sorting, infinite scroll and other utilities.

In the example showcasing my crates I also try to show that you can make a pretty ui with complex layouts using egui (check the gallery and chat example): https://lucasmerlin.github.io/hello_egui/

I've had to spend a lot of time improving egui and it's ecosystem in the process of building my app but it seems to be worth it.

If you're not building a graphical app it probably makes more sense to use something like tauri or flutter as the gui to build a cross platform app with rust, at least until it's gui ecosystem matures.