I just tried out the pitch correction on my Voice live machine, and it's really cool, yet strange.
It will allow you to do vibrato, but you really have to know what you're doing, and have it set to the key you'll be singing, and or theremining in.
As far as theremin newbs go, this might well be a great way to get someone used to finding where notes live in space, but I'd be cautious about letting them use it too much as it's best to learn from natural experience in the long run.
I find that this type of gear is great in the studio, but I'd be very nervus about using it on a live stage due to all the setting up, and changes that have to be done with this thing. There's a knob which allows easy access to any of the hundred or so presets, but still, it's pretty complicated.
Playing with correction turned on reminds me a lot of my 20 dollar Junior Theremin in descrete mode, only with more octaves. ;)
The nice thing about the Voice Live, is it has three correction modes, hard,(like the Junior Theremin, and Cher's gear), medium, and soft correction which gives a slightly more portamento change between notes.
Oh, yes, there's a set of microphone jacks that allow you to sing into this thing.
Anyone thinking about getting this model, the correction is located from presets 71 to 75 which also includes two forms of pent corrections.