So far, I really like MXSPEECH. I don't use it professionally though. My use case is to change long emails into audio-files to save me some time. The voices I used so far were a bit robotic, but they do what they have to do. Clearly "reading out loud" the text I used as input.

I might use this in the future for content creation as well. When I do I will come back for a more thorough review.