I use it and have the monthly membership. Its great for "reading" books when you don't have time to actually sit down and read. I have a shyt ton of reading and studying to do already for school so its the perfect medium for me to "read" books while in bed before I fall asleep or on long drives.
Highly recommend it. With a the monthly sub you get a credit (sometimes more depending if they have a special) to get a free book every month. Love it.
Audio books are much better quality than I think they used to be too. Though some are duds. However, reviews will help you decide which ones to check out.
Perhaps my favorite so far was In Cold Blood (though this book has some

moments from the main characters which is balanced by the fact they're psychopath losers.)