Hebrew has similar issues, and in particular no device that only uses Adobe Digital Editions for ePub will work with Arabic or Hebrew, see
eReader for the Hebrew reader. The PocketBook's look like they may support Arabic, using FBReader for ePub, but I don't know if that is the case for sure. At a minimum, you would need a font that included Arabic characters because FBReader does not support fonts embedded in an ePub.
Note that many ebook readers will support Arabic in PDFs, but this will only work well if the PDFs are formatted for the small screen size (i.e. have a small page size).