Just visited the app store and found the new Stanza for iPad. Looks great. At least peer with Kindle for iPad and perhaps with iBook. Lots of options on appearance. Adjustable fonts and sizes; defaults very readable. Dozens of background/paper choices. No 'parchment,' my fav in eReader, background but "old parchment," sand, and wood.
There are "tips" to help you get started but if you have used the iPhone book apps you will find this app fairly intuitive.
Data and meta data did not transfer; lost all my books. Of course, the books did not transfer from the iPhone to the iPad but I had repopulated. Books did not transfer from the iPhone app on the iPad to the iPad app. Will not update the app on the iPhone until I have at least made a list of the unread books. They will show up under iTunes>youriPad>Applications>Stanza and can be moved or copied.
I find that I choose my reader based upon the source of the book. All other things equal, I prefer the Kindle readers because Kindle/cloud keeps all my devices on the same page of my books. Rarely read on the PC except for text books or research. Still may read on the iPhone, particularly if I wake in the night.