As someone who loves sci-fi novels but doesn't always have time to commit to an epic, I rely on audiobooks while I work or relax. A good audiobook is different from a book for a handful of reasons.

• The audiobook for a favorite sci-fi novel may not exist at all (and therefore cannot be awesome as an audiobook haha)
• The audiobook may exist, but may be poorly produced, ruining a great story.
• The audiobook may be exceptionally well produced, with fantastic voice actor(s), and may actually add another level of greatness to the story.

For me, a couple of examples of amazing audiobooks would be The Lost Fleet series and the Old Man's War series. However, when you look around, it can be hard to find a good sci-fi audiobook, so that's why I think it would be great to have them on this list. If added, you could add them as a seperate category, like with Movies, or you could treat them as a subtype of books, which, I think makes less sense.