I too have owned many arranger keyboards with onboard vocal processors, and a half dozen stand alone vocal processors. There now seems to be so little difference between the processors that if the singer has a high quality voice, the audience would not be able to tell the difference.
Good luck,
Gary

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PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!
K+E=W (Knowledge Plus Experience = Wisdom.)