I like them both, but I'm thinking a thinner chain /simpler pendant may go better with this dress. Then again, I guess it depends on the length of the chain, and where it would fall on your chest.
My thought process is there's a lot of texture going on with the roushing (which I really like by the way) that it may "compete" in terms of textures. That said, I'm no fashion expert
I agree, depending where it falls on your chest I think the simple one compliments it better. But then again I'm always very simple with accessories because I have zero style.