Piper is great, but nowhere near the quality of the OpenAI TTS voices.
I'd find Piper too jarring for audio books because of the big quality difference, but I actually prefer it for things like AI assistants as I don't necessarily "want" AI assistants to sound perfectly human, and prefer the stylistic choice of having them sound more computer-generated.
I'd find Piper too jarring for audio books because of the big quality difference, but I actually prefer it for things like AI assistants as I don't necessarily "want" AI assistants to sound perfectly human, and prefer the stylistic choice of having them sound more computer-generated.