Originally Posted by Jessica Lares
There's the one problem with iOS reading apps in general. You have to use the File Sharing feature in iTunes or something like Dropbox to load books.
This is not true. Many e-reader apps include browser download engines or access to OPDS catalogues, so they need neither file sharing, nor iTunes, nor Dropbox. It's a myth. On an Apple device, you can also simply click a regular download link in a regular browser such as Safari or Chrome, to open any e-book in e-reader software of your choice. You can also e-mail any e-book to yourself. There are countless other options.
My favourite e-reader software on iOS is the most recent sensation, Marvin. It's astounding. Prior to that, I preferred Stanza. I find both iBooks and the Kindle app lacking due to the extreme dearth of customization options offered to the reader, almost bordering on user contempt in some respects.
If there's a weakness shared among various iOS e-reader apps, there seems to be some trouble with the highlighting functionality. It can be difficult to highlight a passage if it stretches across screens or across paragraphs. Probably some weakness in Apple's API.