This is by far my most frequently worn leo. I'm 5'9.5" and 145lbs and need extra support (I'm a 32 D) and this leo delivers. I wear a medium, but this is so stretchy you could probably go a size down. The seams are super flattering and all around it's a great style. It's held up pretty well, but the elastics on the back have gotten a bit worn (I've had it for 7 months now though, so I'd say all things considered that's nothing!)
Definitely fits true to size, however the front panel is very poorly supportive. I do not need much support, though this leotard offered absolutely none, and I ended up returning it for one with more support.