While I'd not call it "Music" Player for my purposes, I use it since a few years for playback of audiobooks and similar content for which a proper queueing feat

While I'd not call it "Music" Player for my purposes, I use it since a few years for playback of audiobooks and similar content for which a proper queueing feature is highly relevant. It's been great for that, containing all the important features and proper queues. The few issues I had, I sent to the support email as bug reports or feature requests, and most of those have been resolved relatively quick. So, not being open source (or at least source available) is the only remaining concern for me. Still, I'm happy to use it since there are only few mobile applications that have a similar no-nonsense style and still target power-users.