What was released today was a rewrite of the Famous core engine, so you can't really compare it to Angular or React. Three.js is a far better comparison, though the two have different specialties since Famous isn't trying to be pure WebGL.

The Famous team is working on a framework that will interface with their core engine, making things far cleaner at the application level while facilitating less painful integration. Comparing that to various client-side frameworks will definitely make sense.