Yes it is worth it, depending on your circumstances.

I find it very difficulty to find a good live vocalist, so for me it's an essential substitute. The program is about about 75% "there", the main issues being those of the clarity of diction. Why do you think that their demos are in Italian rather than English ?..very telling !

You can see the results that I came up with by watching the youtube link posted above. And like all virtual instruments it needs a lot of editing to add reverb, etc in a sequencer like cubase. I believe that the direct download in slightly cheaper, too.