I have the feeling that the Advanced Voice Mode is significantly worse than when I used it earlier this week. The voice sounds disinterested, and has weird intonation. It used to be excellent for foreign language conversation practice, now significantly worse.

Edit: After using up my 15 minutes for testing, I have to say that the new voice is actually not bad, although I was used to something else. But it has a very clear "artificial" quality to it. It also sometimes misinterprets my input as something completely different than what I said, for example "please like my video and subscribe to my channel".