I think that the Waves Tune is better that the Auto Tune because it sounds much more natural.
Also, i saw a funny bug with Auto Tune under Logic. when you in graphic mode, and you jump few few samples/bars/seconds forward, the Auto Tune pich down the Vocal. You can't work like that.
Also, the Waves Tune graphic is much mire clear to the eye than the Auto Tune.
And also you have this sine sound that helps you in case you don't know
Characters.