The thing I liked about the princess was that they didn't make her secretly evil, or obnoxious, or any of the things they usually make 'rival' female characters. She was a genuinly lovely person, and the onyl reason Arthur changed his mind was because he loved another. Nice change in the usual TV universe.
In other thoughts: God! Can Arthur find out about Merlin like soon, please? That continues to be something that irks the heck out of me.