I'd suggest the Kobo Libra H20 (7 inch) or the Kobo Forma (8 inch) screen. The frontlight has colour temperature control. The Forma has DropBox integration out of the box. Both are hackable though neither can be rooted or jailbroken since Kobo does not lock down their ereaders. If you are using the Kobo store and syncing the books to your Kobo ereader, it syncs to the Kobo iOS app (there have been on and off issues with this). They do not have audio support but I'm not an audiobook fan since they are so bloody slow -- the narrators don't seem to be able to speak at 1000 WPM
and I do read at that speed.
Now, I don't have the biggest pile of Karma, and my Karma ain't the fanciest, or the prettiest. But it is honest Karma, dug out of these hills post by post, pun by pun, smart ass comment by smart ass comment. I have toiled under the oppressive gaze of the green meanies, and scuttled like a rat avoiding their fearsome bolts of moderation. 