Apple vs Spotify
I can't see it taking many existing Spotify customers unless they come up with a way to import Spotify playlists; which users have painstakingly built up over years.
There's a kludgey way to do it via Beats but it's not ideal or even available as the Beats servers struggle under the weight of new sign ups.
Unless Apple is able publish a tool that let you compare the availability of tunes on your Spotify playlist and then import it, then I think they'll struggle. It also needs to fully integrate with the BBC's excellent Playlister service.
Until it does all of the above, Spotify gets my money.
Biting the hand that feeds IT
