In an interview with QuickCouch, Rocky has said when we first began recording rap songs he would use his iPhone to do so, and then his producer would edit it in Audacity, Rocky himself also said "it's just as good as any mic if you know what you're doing".
Okay, the form factor of the iPhone 6 is terrible. They even made the mistake of putting the 'exit' button right where you put you thumb when making a picture. But it OS is perfect. That's why I still prefer iPhone over Android.