I like it better yes. But I think I would like it more on a brighter color so the black on the necklace can stand out a bit more. But it does look nice like that, just not as much of a "statement", kwim?
I don't think it works with that kind of neckline. I've seen it done with patterns & look cute, but like the others have said, there def needs to be more contrast if you've got a pattern.