After successfully implementing a project with React.js + Backbone models and routers, I'm now sure Angular is both unnecessarily complex and limited.

One of the nicest things about React.js is not having to deal with such a layered architecture, you work at the right level of abstraction ("components"), and those components are composable. Some people freak out with JSX but it pays off to finally have a proper GUI pipeline for web apps instead of manipulating the DOM directly, or being limited to directives embedded in HTML.