Just had this delivered from Next and I'm really impressed with it :) I'm a size 14, 5'5" and it's very flattering over my black skinny jeans. I'd say it's long enough (on me anyway) to wear with tights as a dress as well.
It is quite itchy though, so you need to wear a long sleeved top underneath. It's quiet generously sized as well, I could probably get away with a 12 but don't like things too tight around my tum 