I watched 'You're Beautiful' a long time ago and I was still very fresh in the Kdrama world (it was my 3rd or 4th drama altogether), but I remember quite enjoying it. Then again, maybe if I watched it when I watched Cinderella and the Four Knights, I wouldn't quite like it as much.
I remember that I had really high hopes for CATFK because it has one of my favorite tropes in it - the reverse harem trope. Unfortunately, this theme is really underdeveloped in this drama. The female lead started off as an interesting character and quickly became really bland, the 4 rich guys theme was also not really that well explored and there were actually only 3 in there, the evil stepmother was too stereotypical and had zero depth to it, and the second female lead was totally indispensable. All in all, it's just one of these dramas that you watch or don't and forget as quickly as you lost interest in the plot 5 episodes in.