That's cool, specially for that cost.

I think if the ePUB and the OS are in the same language, it should (?) work, although I haven't tested it.

Longer texts work the same, I'd say. Of course, they take longer to TTS. I've listened to 2 whole books already and it felt pretty good. I've never used NotebookLM, so I can't say how they differ.

Sometimes it gets a bit messy around punctuation, but I've never had to go back and listen again.

If I interpreted the "prosody" part correctly, then there is some intonation, but it doesn't mimic emotions, so it's very basic. For example, it will slightly differentiate "Shut up" from "Shut up!" (with exclamation mark).

I did look for some options at the time, but wasn't satisfied by them, specially because of cost. I even found a ~6gb container that would supposedly do this. But in the end, I already had the tools to produce the audio, so I just needed to orchestrate it.