Story
Original and meaningful at the same time, this drama could be divided into 4 parts.
Part 1 - Training camp and teamwork: how to create a team with 2 groups of people who apparently don't share any similarity.
Part 2 - Marriage or not marriage?: A very great part as heartwrenching as heartwarming
Part 3 - Club M & betrayal: The drama goes dark & more political, like really. This is by far the cruelest villains I've seen.
Part 4 - Resolution?: It gets a bit draggy there with events that should have never happened. (Baby Boring Guy forever)

Acting/cast
Lee Seung Gi is incredible. He starts arrogant and snob as many of his other roles but becomes so mature and strong from ep.8. He fits the role perfectly and I can't imagine anyone else as Lee Jae Ha.
Ha Ji Won is queen. She learnt the North Korean dialect and intonation. She's cute, naive but also strong and badass.
Jo Jung Suk is soooo underrated, loved him from the minute he appeared. Eun Shi Kyung is the perfect blend of innocence and responsibility. The perfect friend: LOVED HIM.
Lee Yoon Ji is also perfect, I wished they could focus a bit more on Jae Shin & Shi Kyung relationship.

Overall, the characters seem strong and impenetrable but show so many weaknesses and fragility. It's a good insight in the life of royal personalities whose image must be strong for people to feel safe but in the end, they are only humans too.

Music
I liked it but won't be remembered.

Rewatch value
Definitely yes.