Nota: I share the opinion of the guy who made the feedback at VST4Free. It has never worked correctly (either in my Reaper nor in my Mulab, in my opinion the issues were not at all DAW related). I found it rather crappy.
There are excellent harmonizers, if you want some other references.
I had already found it in the link you share in your post, but thanks a lot anyway.
I've tried the plugin but it seems it doesn't work (I use cubase ai7) or, at least, I don't know how to make it work.
I know several harmonizers but I'm looking for one that works in the way this plugin is intended to do. I mean, split the keyboard, play chords in the left part and, at the same time, play a melody with the right hand so harmony is added in real time, according to the chords played. (like in a Yamaha psr500 I had long time ago...)