Main differences are that it also targets Linux+WebAssembly, and it's meant to be Pixel-Perfect so it would look and behave the same on all platforms by default.

It also offers a variety of additional packages out of the box and aims to be an end-end platform instead of solely a UI framework: Hot Reload, C# Markup alternative, a toolkit of mobile-first controls, design systems, reactive state management (MVU-like), recipes for Authentication/Navigation/Logging/DI/...