I tried on the xs in store in crimson (i would need petite) - the color and fit were very flattering on me (pale skin). the dress feels very silky, i love the back, how it ties, and how high the neckline was on me in the front. the little flutter at the bottom of the dress is also a nice touch. my only concern was whether this looked like a negligee... i think i would buy it if i had somewhere to go, just not sure the fabric is appropriate for work... 

reference: 115 lbs, 30dd, 26.5 in waist.