I was a little worried that it wouldn't fit when I put it on for the first time - the shoulders are very narrow - I'm 5'9 and ordered a large. I do like how it looks but have a couple complaints: no built-in bra (I'm a 34D and obviously cannot wear low-cut leotards), fabric is too shiny (it kind of looks like a wetsuit and would be better with a cotton/stretch blend) and the legholes are too small and cut too low (it would be better as a jazz-cut style).
Other than that, it's great. I would recommend a size up if you're tall or have a long torso.
I'm 5'5 and around 120 lbs and I got a medium and it fits perfectly. There is also plenty of support for girls with larger chests. Definitely think about ordering up or else it will be nearly impossible to get on. All said this leo is awesome.
I just got this leotard and have already worn it twice in one week! It fits great and is really slimming. The fabric is shiny and seems like it will last a long time. I highly recommend this leotard for a any dancer ballet or modern.