Sunny,
The 2100's harmonizer can be used for professional performances, and IMO sound nearly as good as some outboard devices. It does not have the rich, full sound of the Digitech Vocalist VR, but it's close enough for most venues.
Cheers,
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.)