The main problem i'm having is that there is not the note separation that Melodyne has.
Melodyne separates every note so it can be worked with and it is adjustable whereas so far it seems like Logic doesn't see every note hence it is hard to adjust every nuance you may wish to. You can use the scissors tool and separate the notes further but it is definitely not the same elegance as Melodyne.
This may come in time i don't know?
Having used Melodyne for a long long time it may just be that I'm use to that and I do find personally that the first software I use tends to be my favorite!
The sound seems relatively very good without too many artifacts probably consistent with Melodyne IMHO.