Aiseesoft iPad ePub Transfer for Mac is a sort of backup utility. It allows you to connect your iPad and download any PDF or ePub eBooks that you have stored on it. Additionally, you can use it to put content on your iPad. You can only upload ePub and PDF books to it, though.
The graphical user interface consists of two panes. The one on the left shows all the iPads connected. Under each device, two folders will be listed, one for PDF files and the other for ePub files. The pane on the right serves two different purposes. The first thing that it does is display a summary of your iPad. It will show your iPad name, its type, capacity, and firmware version, along with the serial number and format. It will also show how much space is used in audio, video, pictures, books and other data and other data. When you click on ePub and PDF, located below your iPad, under the Devices pane, all the files of that format stored on your iPad will be shown. You can easily copy those to your Mac.
Perhaps what is more useful about this app is that it lets you put content on your iPad. If you click on the "Import" button, you will be asked to select a file which will be transfered to the iPad. In my testing, after selecting the file, the iPad synced briefly, and when I opened iBooks, the ePub file was in my library.
All in all, this app works very well, it is easy to use and affordable.