I personally like wxWidgets:
https://www.wxwidgets.org/
It's open source, the code has always felt reasonably clean to me, and it gives your apps native look and feel.
It's open source, the code has always felt reasonably clean to me, and it gives your apps native look and feel.
And it is ridiculously fast compared to alternatives.
I'd like to know what the "native experience" is supposed to be, but I have no idea which of the numerous Microsoft UI APIs is officially current. So far I've just punted and I'm using macOS shapes and sizing and using the colors from the Metro? style; at least it will look tasteful and not stand out too much color-wise.
That's the one. Everything else has never gained enough traction.