I am testing nativescript and performance is truly native and very small binary build, and one codebase for both android and IOS (not web compatible tho). It have Firstclass angular support. The UI is with XML and CSS , so i think emberjs can make it support easily.
Angular guys are using it to develop really cross platform app (Combined with Electron for desktop, Nativescript 2 for IOS and Android ) https://github.com/NathanWalker/angular2-seed-advanced