One of the most difficult hurdles app developers have is getting users to go past the login screen. As Fool contributor Chris Neiger points out in this video, Google Play Music lacks the ability to sign up directly from an iPhone, which creates a huge barrier for users to adopt the app. They have to go to their computers and then come back to their smartphones to login to the service. Chris thinks this will hurt Google and help Pandora and iTunes Radio.
That leaves iTunes Radio and Pandora battling it out for iOS users' music-streaming habits, and for now it looks like Pandora is winning that war.