Firstly the cinematography is high quality like a big budget movie. Beautiful countryside and settings. The chase parts are exciting and the main love triangle is actually quite involving unlike some older melodramas. But the quiet moments and the subplot and some secondary characters are boring. You can fast forward through them. 16 episodes would have been better than 24. Some chasing around is repetitive. The cast is right for their roles. Jang Hyuk and Oh Ji Ho are convincing. The men look and behave like men and the women look like women. Lee Da Hae is sweet and believable and her character isn't annoying. Their story is quite passionate. Unlike the recent costume dramas where often the men are too androgynous looking, the cast here looks convincing.
As far as big epic Joseon dramas are concerned this is a change from the usual ones that are stuck in the palace with the court intrigue and concubines and eunuchs. Worth watching.