I ordered the blue one in XL because I purchased a black one in XXL but I found it to be a little loose; however, it was extremely comfortable and still form fitting.  The blue one in the XL fit nicely but the length was much longer than the XXL I previously purchased.  I LOVE both dresses - the blue one is vibrant and the black was very glamous at my awards event.  I can hardly wait for my next awards show so I can wear this blue one.  Great dress!