For me personally, I like to be in charge, finding my own specific tunes I would like to hear, combine records, tunes, into my own playlist. Of course I pay for the services so I don't hear any adds but the payment, about 10 euro's a month, is fine for me since you also get better quality as well...
Other thing about Apple that I considered to be a disadvantage is iTunes. I never liked iTunes due of it's restrictions towards different formats when playing video on it and the way the whole interface works. I find Spotify so much more appealing looking at the more user friendly interface and not to forget all the extra free add-ons. Not all of them are interesting, but I do like the plugin SoundDrop a lot and the way it works with third party recommendations like
http://www.perfects.nl/perfect-mood-swings/ (Dutch) or even when you would like to sing along it offers a variety of plug-ins to hear the music together with the lyrics, even showing the right line in sync with the song. And last, but not least, the community behind it. You can share everything on facebook, even showing directly what you're listening, invite people over in a music room, let people / friends select songs to play where they all can listening to simultaneously.
I think, therefore, Apple is to 'late' and is fishing behind what's already hugely popular, offering a service that's not new at all (last FM, Pandora, Spotify) with a huge lack of options when comparing it to what these other formats has to offer.
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So you don't get to choose what you listen to?
I'm not sure if I'm missing something but how will this be better than listening to a normal radio station?
Answer: it's not
I guess if you like Springsteen, as example, it will give you the choice to listen to music like Springsteen, but that's basically it. The on;y 'new' aspect would be that if you hear a new song you can skip back to it's beginning to hear it all over, that could be handy when you jump in a streaming radio station...
But in Spotify, when using Sounddrop for example where all the people in the room can suggest music, OR when using a radio station option, that is exactly the same what Apple will bring out, you can directly select the song you're listening to and put it in your own playlist. With a payed account you can even download it to you smartphone for offline use.