Apple’s statement to Re/code regarding offline listening:
As an Apple Music member you can add anything from the Apple Music library — a song, an album or a video — to your collection. And that’s just the warm-up act. From there you can create the perfect playlist from anything you’ve added. You can save it for offline listening and take it on the road.
It’s kind of unfortunate that users will have to manage there songs for offline use manually. It would be great if Apple Music automatically cached songs on your device that it thinks you’re likely to listen to if you were to go offline. That’s the kind of experience that could get me interested in the service.