My impression : A perfect blend of drama, comedy, action, (b)romance and intrigue, flowing seamlessly from one to another. The audience rides a roller coaster of emotions (mostly laughter) - there's hardly a dull moment. The ending is perfectly satisfying - a happy ending too, except for the villants of course. Great casting, script, direction and production. The OST lends depth to the story telling.
One major complain: it's hard to move on from this drama and its characters at the end of episode 20. I want more! This show sets a high standard, and subsequent drama may not measure up. I'm suffering Mr Queen withdrawal symptoms LOL.