Let me be the first to say - downloading and installing as we speak.
First impressions: I like the bar. But not quite enough to leave it on in a book for the whole time. I know that this sounds harsh, but how about a toggle on/off option?
(long press, or press in lower section of the screen)
I can almost feel the complexity skyrocketing and the problem potential exploding, as Im writing this, but you have to ask - you really do. And by you - of course I mean me.