[Libbum]

For android I use "Listen Audiobook Player". Automatic progress tracking for multiple books, and generally all round great for daily audiobook usage.

[freedomben]

I also use Listen Audiobook Player [1]. Loaded with well thought out features. The app also saves your progress/stats in a json file in your audiobooks directory, so you can easier move it to a new phone/tablet whenever you want.

[1] https://play.google.com/store/apps/details?id=com.acmeandroi...