you could also try
3D Issue. They normally focus on PDF to page turning flash and HTML5 but they also have a component that will allow you to create an eBook.
The problem with converting a PDF to a eBook is that there is no extraction alrogithm that will take the text and images out in the write sequence because the design of PDFs is done by hand so to speak.
Whatever app you choose there will be a certain amount of work involved.