I'm road-testing libgdx and so far I'd recommend it. It's quite mature and built upon solid libraries underneath; open-source too and the code is clean so you can easily go in and follow what's going on under the hood.
For graphics you can either play with OpenGL directly or use higher level of abstractions (such as SpriteBatch). It even comes with a nice JNI wrapper for Box2d.
No direct support for iOS but through the magic of GWT you can compile to javascript to make an html5 app out of it. Then you could choose to either deploy that online somewhere and leave it at that or you could embed it into a native wrapper which allows you to stick it on the app store as a native app.

I'm road-testing libgdx and so far I'd recommend it. It's quite mature and built upon solid libraries underneath; open-source too and the code is clean so you can easily go in and follow what's going on under the hood.
For graphics you can either play with OpenGL directly or use higher level of abstractions (such as SpriteBatch). It even comes with a nice JNI wrapper for Box2d.