iTunes Radio is freaking awesome. First, it's just as easy as it is with Pandora to create stations but you can switch from one station to another and back and pick up exactly where you left off. If a song plays that you like and you want to listen to it again ... no problem, you can start over or listen to the song all over again. Freakin' awesome. Second, the total lack of ads is killer (I was already an iTunes Match user so ad-free listening is complementary with my subscription). Third, on the iPhone it is way cleaner of an appearance and experience and use with Siri is awesome. I have already copied all my Pandora stations over to iTunes Radio and honestly don't see myself going back. I haven't deleted the app yet just in case but I have a feeling it's only a matter of time.
I know Pandora says they aren't worried but they should be. There are about to be millions of less users of Pandora.
And, yes, I am short Pandora. Putting my money where my belief is and I have all the time in the world for it to pan out.
But in all seriousness are you not concerned about iRadio? I do not view it as a "Pandora Killer" as so many other shorts have lauded it, however, it is in my opinion a very real threat to continued Pandora growth.