This thing does EVERYTHING. It's a stereo preamp+converter, a stereo effects unit (digital or analog), a four part harmonizer w/mixer & midi, a pitch corrector, a stomp box, a mix/effects pedal for singer/guitarist, and a song arranger.
Listen to the 100 presets to really understand this thing. Choir, barber shop, cartoon, giant, mice, robot, gregorian, etc.*
The features are EXTENSIVE. Read the manual. Pitch correction is simple: key, scale, window, attack, level. Four part harmony is something else. Gender, age, vibrato oh my. SO many vibrato styles and settings. And velocity stuff. http://www.tc-helicon.com/download/m..._rev102_US.pdf
The basics for for harmony are scalar, chromatic, chord (maj, min, etc.), custom, or midi. You tap the pedal to choose song key. Can be tight or loose timing-wise. Seriously, read the manual, it all works great.
The unique thing is that it has professional live features, like hard wired microphone out (a clean channel to send to the board). But it also has studio features, like s/pdif in/out. Nice touches like selectable output level (+4 etc). All analog outputs are balanced. This is a professional unit! Oh, and the reverb is very nice.
One cool feature: sing a note, press "hold" and the note sustains until unpress.
The mic preamp. It is a bit noisy. I don't use the mic in the studio. It's fine live though.
Reliability might be a tiny issue. Mine locks up on rare ocassion. About as often as I break a guitar string.
By far the most fun piece ever in the studio or live!