This shirt is awesome.  I am 5'5" and about 120-125 lbs, I believe I purchased the small.  It fits great, is super comfy and I absolutely love the color.
You just have to be careful when you wash it.  Mine has gotten a little. It thinner or more worn since washing it and I've always washed it by hand and hung it up to dry.
The one time I used the delicate/hand wash setting on my washing machine and then hung it to dry like usual, it looked a little different and seemed a bit more worn out or something.
Overall though, I love it and intend to order more of these in different colors- as well as one or two for my sister as a birthday gift!