WinUI 3 builds on the legacy of earlier XAML-based frameworks, and isn't entirely a brand new product (unless you're on non-C#, then the whole C++/WinRT API is

WinUI 3 builds on the legacy of earlier XAML-based frameworks, and isn't entirely a brand new product (unless you're on non-C#, then the whole C++/WinRT API is brand new, and actually kinda nice (speaking from having used Gtk and Qt before)). You shouldn't be wary realistically because Microsoft has spent almost a decade grinding away at something that needs to exist for both Windows to survive, and for Microsoft to stay relevant in app design. The existing code that makes WinForms, WPF, and WinUI 2 apps (the API in UWP) also has been reused or extended by WinUI 3. Microsoft just wants app development not to suck. They designed C# for a post-Java world for this goal, they rebooted Visual Studio years ago for the C# era to achieve this goal, they took XML out of the places it didn't belong and put it into the places it did belong (ex: XAML, for actual real document-style code autogeneration) for this goal, they switched to Git to handle their famous monorepo to accelerate development of Windows, they bought Github because of how much they used it internally (and made their job so much easier than their kinda shitty internal mixed heritage VSS quasi-fork), and they're one of the largest users and committers of the Linux kernel itself and would love if they could run their own modern MDL2/Fluent(=MDL3) apps on Linux natively.