Adding the piper voices is a game changer!! Thank you Dev.
Initially, I was pretty unhappy with the robotic voices and decided to read the reviews and found the same complaints. Then I saw that there was an update a week ago and, lo and behold, you can now add custom voices from piper that sound so much more human. It's a night and day difference. Makes this so much more worth it now. Even though it's still in the experimental phase, it works just fine for me.
I urge everyone to try it out in settings.