I didn´t really look at the Kabus demo but if it really got done with A6 then the shadows can´t be that great. A6 stencil shadows were really crappy and A7 stencil shadows aren´t much better. They are slow, the mesh must be closed, they project through everything, they don´t react to lights correctly, they don´t support transparency, self-shadowing looks really bad,...
Even static light maps aren´t that great in A7. The map compiler is slow and produces many ugly artifacts and importing externally rendered solutions often is impossible or a huge pain.
So I don´t see how A7 is that great in the shadow department.
A7 commercial has stencil shadows and render to texture.
Unity indie has full multiplayer, PhysX instead of ODE, a vegetation system and many other nice features which are unavailable in Gamestudio.