Mp3 vs Mb4 on Android

An AudioBook club I belong to allows me to choose the format I download my purchased audiobooks in. My options are MP3 & MB4.

I generally download them to my laptop (running Windows 10), so I have a back up copy, then copy the file onto my tablet for listening. My tablet is a Samsung Galaxy Tab 4.

I've always downloaded MP3 formats, because I was under the impression that MP3 was best for universal listening devices, including Android, whereas MB4 is primarily for Apple/Mac devices.

That said, I've noticed some of the MP3 files I download from this club have subpar audio- and it's not related to the tablet, as other things play fine. I recently read somewhere that mb4 formats are higher quality- is my understanding of them incorrect? Should I be using the Mb4 formats, or are they only compatible with Apple and Mac?

TIA

 

Downpour. They're a division of Blackstone Audio, and their downloads are DRM free and work on any player. I do use Audible as well, but they play through their own player and download in their own format automatically to the player. Admittedly, their quality (and selection) is superior, but Downpour is substantially cheaper and I prefer them since they can play on anything; not just their player.
Not all of DownPour's audiobooks are poor quality audio-wise, but some are & i wondered if mb4 vs mp3 would make a difference.