I believe I purchased mine at Manny's Music in NY.
This machine is the best thing that can happen to your voice besides singing lessons. It corrects your pitch, fixing bad notes in real time, and can even add realistic vibrato and extend your range. It has a MIDI input which can be used to "play" your voice, enabling you to make your voice sing fast, complex runs, etc. It can even create special robot-like effects. I go into more detail about this and other equipment I own at my site, Motionizer.com, address http://www.motionizer.com
I don't have anything negative to say about it, except maybe the control panel takes a little getting used to. They tried to simplify the unit by providing only a few buttons; but sometimes, that only makes a product even more complicated...
It's small, light-weight, and generally well-made. I like the big, clear display.
I highly recommend this unit. It was a great idea, and it's a big help for marginally-fine vocalists (like me.)