I got a tri-blend tank. I got a medium, but wish I had gotten a small. It's huge. In normal shirts at the mall, I'm usually a medium, but at the small end. On the AA blanks, I would get a medium, it would fit relatively loose. In the current blanks, I like the smalls (which are still too big, but meh).
The women's tanks are really stretchy and the sleeves are cut really long/neck cut really low.