When comparing Smart Audiobook Player vs CastBox, the Slant community recommends Smart Audiobook Player for most people. In the question“What are the best audiobook apps on Android?” Smart Audiobook Player is ranked 1st while CastBox is ranked 6th. The most important reason people chose Smart Audiobook Player is:
Option to shorten dead space between words. (Allows for faster playback without it sounding like chipmunks.)
Ranked in these QuestionsQuestion Ranking
Pros
Pro Reading speed changer
Option to shorten dead space between words. (Allows for faster playback without it sounding like chipmunks.)
Pro Volume boost + equalizer
Pro Very good at saving your position
Especially if you pay for Pro which gives you cloud sync for your position - so it's easy to restore and pick up listening even if you switch phones. Even if you don't pay, your position is stored in a file inside the book folder which you can easily copy.

Pro Auto rewind after a long pause
Goes back up to 30 seconds depending on how long the last pause was.

Pro Auto-theme app from cover art

Pro Completely customizable
So many customization features: playback position format, equalizer, playback speed, headset button actions, sleep length, skip lenghts, and more.

Pro Auto-find cover art for local books
If your book doesn't have cover art, the app can search for it for you.

Pro Reset the sleep timer with the accelerometer
Just leave the sleep timer set to 20 minutes and leave it on all the time. If you are walking or driving, it stays playing, but if you are listening in bed, it turns off on its own. If you are still listening, just give your phone a shake when you hear it start to fade and it will keep going for 20 more minutes.
Pro No official store
The author only profits from a better listening experience, not from user lockin due to no other place to get books.
Pro Supports notetaking
Written notes with a timestamp in the file, organized according to book (i.e., folder).
Pro Reads your own audio files
Copy your audio files into a folder, and this will assemble them into books based on the folder they're in.
Pro Wide coverage
This is a must-have podcast app if you're living in another country apart from the US. CastBox supports and shows podcasts from more than 70 countries.
Pro Vast library of podcasts and audiobooks
Pro Award winning interface
Optimized to help you hear what you want to hear.
Pro Adjustable playback speed
Slow down until 0.50x and speed up as fast as 3x.
Pro Weekly updates & improvements
The developers try to keep the app updated from bugs and to make it a world-class app. With ever-growing features and improvements, it even competes with the best podcast apps out there.
Pro "Trim Silence" feature
Skip the silence and listen more to words.
Pro Tag podcasts
Create tags to organize your podcasts.
Pro Pro Subscription available
Remove ads, "customize home page" feature, and more for total productivity.
Cons
Con Needs manual to help with some features
Con Next episode on Playlist doesn't always play after current episode finishes and not all episodes of subscription show up
Con Very invasive ads in free mode
They really degrade the experience in the free mode.
