This was an excellent kdrama. The production quality was excellent and the acting was stellar, especially Namkoong Min. He carried the attitude of an arrogant, worldly man who hid a heart of pure love so beautifully.
I was really happy with the extra episode at the end. The series could have ended with a happily ever after vibe at the end of episode 20, but the additional episode added so much more depth to the ending.
The only (very slight) negatives I can cite were -
1. I would have liked to see a bit more of a wrap-up on Ryang Eum's story.
2. Portrayal of Gil Chae's immaturity in earlier episodes went a bit over the top. I mean, they were in the middle of a war and she's whining that she thinks he's a player. ugh
Overall, though, this kdrama gets two thumbs up from me.