I think they are both hot, but in different ways. Appaho is smoking hot, while Kangchi is so cute that it makes one hot. I know when I saw Appaho in episode 14, I died because he burnt my heart.
Speaking of episode 14, I'm pretty pissed at Master Dam, not so much for arranging the marriage between Yeo Wool and Tae Seo, but for telling Yeo Wool that she can't be a part of missions much because she has to learn her 'wifely' duties. I'm sad about the marriage, but even sadder tjat Yeo Wool faces a complete reversal of her character. Regardless of the decisions that Master Dam had made in regards to Kangchi in the past, I at least respected that he allowed his daughter to fight alongside the men and train them.*Spoiler