Originally bought a S and had to exchange for a M. I am 5'7" 137lbs, I usually wear a S, but my torso is a little longer than typical that is why I decided to exchange it. I wanted to be comfy and not have it ride up. It worked out.
Had my eye on this piece for a while, and waited until it was on sale to buy. Thank god I did because I would have been livid paying full price for what I got. Beautiful print, and very soft fabric. However sizing is way off. I ordered a medium (I’m 5’5”, ~125) but found that the piece fit like an extra small. It wouldn’t even go over my shoulders. Let my sister try it on after deciding I wasn’t going to keep it if I couldn’t where it. She’s a size small and it still didn’t fit. The whole cut was a bit strange, extra fabric in places there didn’t need to be, and not enough in others. I even turned it around to see if it worked better that way (to no one’s surprise it didn’t) They don’t do returns on body suits, so we’re stuck with it. Not worth it IMO.