more options, being able to get new titles right away, not having to put something you want to read/listen to on hold and wait for your turn, being able to keep it as long as you want it without worrying about renewing.

that being said i still prefer overdrive.

audible is purchased stuff, mostly. it's got a wider range than you'd get from your library and there are some general 'member freebies' that can be ok. I have no info about overdrive. most of the audible books I've picked up have been well done/produced/performed by narrators.

I love OverDrive, my local has on average 1,000 audiobooks available at any time.