Excellent
Have had this app for years now; though I prefer to select and download offering at Librivox directly, and save them in iTune, it has been quite useful on long trips as to get fresh contents, and once during a brief unexpected hospital stay.
Negative reviews based solely on content should be dismissed out of hand, since it is obvious these reviewers missed the point: AP gives access to open contents from many sources, but does no create this contents. Such criticism is akin to blaming Apple for offering a bad movie on iTune!.
Not that contents is bad. Librivox, for instance, provides books read by volunteers - thus the quality can be uneven. But they also have many outstanding voice actors creating free audio books with quality on par with commercial offerings costing $10, 20 and more. Other free sources are similar. Look at Smokestack Jones reading H.P. Lovecraft on Librivox, for example, for some great quality material.
Technically, this apps interface shows attention to details, is clean, uncluttered and straightforward. Aside from one buggy update which was promptly corrected, stability has been excellent, on all Touch models from 1G to 3GS. Finally, unlike many apps in this category this one does not impose any limits on the number of titles it can contain. Why pat for apps giving only a handful of preselected titles when you can have anything you want?
I have never had any regret in spending my money here - but dont take my word for it, try the somewhat limited free version if you want to see if this fits your audiobook usage pattern.
psa about
Audiobooks - Thousands of free Audiobooks and Podcasts., v4.8.1