[agf]

I see why you'd think a human-read one would be better, but in my experience that's not the case. It's not that easy to read out loud and actually sound good.

I've spent a fair amount of time listening to free audiobooks (https://archive.org/details/librivoxaudio) including many that are out of copyright like these, as opposed to modern but in the public domain.

After listening to a few minutes of "Frankenstein" on his site, I would say that these OpenAI generated voices sound better than almost all of the human-read ones on Librevox, both in audio and performance quality -- these are voices that are designed to sound good, and they succeed at that.