Underrated vocal/speech synth software

[sapplerx]

Are there any vocal/speech software that you think not a lot of people use?

To clarify I do not mean characters like Miku or Gumi, like any engine

 

[Prism]

I think East West's vocal libraries get overlooked a lot of the time. Granted they are made mainly for background vocals and made to be blended in with human singers, but they offer something the others' aren't really doing.