I did feel that aspects of this drama were too drawn out (for example, the prescription, death of the previous Crown Prince, some of the lessons), which took away from the feelings of anxiety and threat a little. Old ground was covered once too often, instead of enlarging on other parts of the story, like the shocking (for the time) revelation about one of the princes.
At odd times, I also felt the Queen's decisions were out of character and naive, when she wasn't at all (like being too trusting and leaving things too open to opportunity for their enemies).
If not for that, I'd have given a 10/10.
Everything else I loved. Kim Hye-soo as Queen Im Hwa-ryung was brilliant. Certainly not a typical Queen, she was very intelligent, opinionated, witty, feisty and compassionate. Even if she felt it, she never showed jealousy or was unnecessarily bitchy to the King's concubines, but did exert her authority when needed.
The concubines were a proper mixed bunch too.
I loved that whilst tough, the Queen was warm as a mother and didn't push her sons for her own benefit, but for their survival.
The other characters were really mixed and some of the ministers, whilst involved with plots and schemes, were taking sides to protect more than themselves and were not all power crazy; that gave this sageuk a different edge.
Kim Hae-sook (a favourite actress) as the Queen Dowager, with her poker face and fake laughs, was brilliant... the first time I've absolutely loathed her! ?
One character I felt so sorry for, but they ultimately became their own worst enemy, so full of hate and revenge.
The plot twists, humour, shocks, moving scenes and ending, all combined to make this a really good watch. One I'd happily see again.