I own it, that was my final choice for an harmonizer.
One of the most important things in a vocal harmonizer, is the ability to modify the formant parameter. This parameter allows to reduce both Darth Vader and Mickey Mouse effects on the harmonized voices. Not all harmonizer have this parameter. Also, I noticed that it is easier to get a more natural result when the lead voice comes from a woman. If you are a baritone, like me, it is a bit more difficult to get a good result.