I do have to say this is really first class - an excellent app already.
Well done - most impressive.
A couple of things to think about next year when you upgrade:
As mentioned before - ability to alter paragraph spacing.
Also - I do like the ibooks shelf system where I can see all the covers in their glorious colour, so something like that would for me be the icing on the cake.
Marvin is now already my preferred reader.
Out of interest - how did the name come around? Anything do do with paranoid androids or ( given the glasses icon) Hank Marvin?