I'm sorry, but I don't like this UI at all. It looks foreign on the iOS as if it were designed for some other device and the ported over. Such neglect for the consistency with a native look and feel is not a "fun experience", it's really quite annoying. My iPhone is not an empty canvas for you to drop an arbitrary UI style on. It comes with Helvetica and a whole bunch of well designed controls. I insist you use them.
That ship has sailed a long time ago. Pull-to-refresh, that-slide-out-navigation-from-the-left, fan-out-navigation, parallax scrolling, all are now common iOS UI tropes that originated nowhere near Apple. Personally I hate that back button - it's huge , but that's a pretty minor gripe in the grand scheme of things. This UI is clean, functional, and its functionality is intuitive. Pretty decent win, all things conside…
I have never been able to used to the back button or the bluish-gray top nav bar Apple insists on using. If I ever spend time thinking about it, I feel like puking, no exaggeration.
But my dislike for the bar is offset by rest of the device.