Gesture based apps are becoming ever more common. They eliminate buttons and simplify the UI as a whole. Gestures in a music app can be very useful and that's what has been applied to Beat.
Beat is a brand new music app for the iPhone that has a stunning minimalistic interface which is mainly controlled with gestures. When you first open the app you're shown the gestures which are used - some app developers say that if you have to show a guide on how to use an app, it defeats the simplicity of it, I don't think that's true. A great example is the pinch-to-zoom - this gesture was not natural at all until someone actually shows you. I was able to learn the gestures needed to use Beat literally within a minute or two.
Also having gestures makes using the app without looking at the screen ever more easier. Say you're driving and you have your phone in your phone holder, you can keep your eyes on the road but still switch to the next song or pause it - you don't have to look and make sure you're tapping the right part of the screen.
The gestures are very simple. Double tap to pause/play, swipe left or right to switch to a different song, tap and hold on the left or right edge to skip through a song - there are many other gestures too.
There are a bunch of different themes available in the app so you can change the colour of the background. Some are locked however, and the only way to unlock them is to do things like share the app, rate the app, use the app for 60 minutes and other methods - it's actually a neat way for the developers to promote their app.
I personally am not a fan of the font. The font used is Open Sans and I feel like it's 'off' compared to the Helvetica that iOS uses. It would be great to see Helvetica used instead of Open Sans. But I will still be making the app my primary music app from now on. I mainly listen to my music when I'm driving and having gestures to control basic functions is a lot more useful than having to look for a button.