I kind of am in a love/hate relationship with this show. I like how this is a show in which the main female lead can be considered "evil". You know why she's doing the things she does, you pity her for it, but also grow to hate her for it and keep saying "Haven't you had enough girl?". Which brings me to my second point. I love the acting, Lee Duk Hwa plays an excellent role as King Injo. He is portrayed very human, he has emotions too. He knows (in my opinion) very well what every one around him is thinking and planning, but he also wants to have someone around him and someone to love him, which makes him, to me, a very complicated and human character. Also Kim hyun Joo plays her role very very good. You pity her for being in her position and fully understand her reasons, but also hate her for her actions. There really is more to all the characters than meets the eye, if you're willing to look deeper and try to understand why they are doing this. If you're planning on watching this show, make sure to put yourself in to their shoes and try to understand their reasoning. Than this show is worth it.
One big problem I stepped on was the repetitiveness and slow progress of the story.