I bought an XL and it's still a little too small. I'm hoping to lose some weight, so I can wear it in the Fall.  I'm about 5'6 and 170 lbs.
It's a bit difficult to put on. You have to first unbutton the front, then unzip the back, then put it over your head. That's a lot more work than most dresses.  Also, the skirt is a very stiff, somewhat heavy material. I will need to iron it. It's pretty, though.