I love the material and mesh on the sides of this shirt, but I was surprised to discover it runs a bit small. I usually wear 6 or 8, 5'7", bust 36", but I had to return the small I ordered in this shirt because it was a little tight in the bust, a little tight in the shoulders, and the arm length was a little short. The M is perfect as I usually wear it over a t-shirt for coverage. It's so light I don't notice I'm wearing it, even on a hot day.