Does anyone have any experience in using vocal harmony-hardware like the TC-Helicon VoiceLive (2) or the Digitech counterparts? I'm looking for a piece of gear that can add good quality harmonies in a live situation. It will be used mainly on stage as a harmoniser for the background vocalist, but I also want to be able to use it in the home-studio.

The TC VoiceLive 2 looks very promissing, but how does the quality of that unit compare to the TC VoiceWorks Plus? Or is the Digitech the winner when it comes to quality voicing? Or are there other companies that offer even better solutions.?
There is no store in the neighbourhood that has these units in stock, so can't play around with them to see which one suits me the best. I'll have to make a preselection now before I can arrange a testsession.