Unreal is much less limiting, and has stellar shaders. And is cheaper--$19 (+5% royalty, if you end up selling something) gets you a perpetual license for the current release of the engine (which can be updated at any point for another $19, or you can just keep a $19/month subscription and always be up to date). Unity requires a $1500 pro license to do any Oculus development.
You wouldn't use C4D with Unreal, though. I mean, you could, but you'd need an intermediate file format. As opposed to Unity, which handles C4D files just fine.
In terms of Oculus apps not being pretty...