Can someone point to a good open source alternative for vocaloid?

I know of Sinsy [0] but I couldn't get it working. eCantorix [1] is very old and rudimentary (it uses espeak underneath [2]).

Searching just now I see OpenUtau [3] but I have no experience with it.

Seems crazy there isn't a good FOSS solution for this.

[0] http://www.sinsy.jp/

[1] https://github.com/divVerent/ecantorix

[2] https://espeak.sourceforge.net/

[3] https://github.com/stakira/OpenUtau