Vue 3 is faster, smaller, more maintainable and it's easier to target native.

Composition API

One of the most significant changes is that a new API that will allow for a function-based way of writing your component, inspired by React Hooks. It lets you encapsulate logic into "composition functions" and reuse that logic across component

Other changes in Vue 3 compared to Vue 2

Virtual DOM rewrite for better performance and improved TypeScript support
Native portals – now called Teleport
Fragments (virtual elements that won't be rendered in the DOM tree)
More flexibility for global mounting
Conditional suspending of component rendering

Smart UI for Vue 3

Smart UI for Vue 3 is available at: https://www.htmlelements.com/vue/.
All components are fully available and tested for Vue 3 web development. API & Getting Started Docs for Vue 3 have been added to https://www.htmlelements.com/docs/