"Picked this up in purple, but the black was gorgeous too. I'm normally a 6 or S, but went with the XS because I'm super short (5'2") and the dress is very long. The cut made it so that I didn't have any problem wearing a size down, and I'm even a bit hip-y.
The shoulder straps are quite long, and I did have to take them in about two inches. (Again, I'm short.) It certainly wasn't anything that I was upset about though. And it's a quick fix.
Overall, AWESOME dress, very fun. Size down if you're short and not too busty or too hip-y."