I am 5'2 about 130 lbs.  I usually wear a Medium, but based on the reviews, got a Large.  I could have gotten away with a medium if I had wanted to because I found the Large to be a bit roomy.  However, that's ok, because I intend to wear layers under this sweater during the winter time.  My biggest complaint is that the sleeves are very long.  It goes beyond my fingers by about an inch.  I guess if you fold it up it's ok.  As for the length of the sweater, it's fine b/c it hits me just at the top of my hips, so it actually looks pretty good.

For the price (I got it at $10), it's a sweater worth getting, esp. since the quality is so nice.  It's a soft, smooth, thick fleece that is anti-pilling (so the label says).  As far as I can see, it'll surely keep you warm in the cold weather, which was the main purpose of me buying it.  The design is cute but the cutting is a little off