I absolutely loved this drama but the thing I liked the most was that every single character was likeable, even with their flaws (and believe me, all of them had a lot; but that's the fun part, they didn't tried to hide it). Gang Nam-soon it's the best and she's also amazingly interpreted by the actress. BTW, every main actor/actress here is great!
But if you are looking for something policial/suspense/too much action, you'll get disappointed. It's part of the plot (and it's well done) but it's not the main focus. It's much more fun, light-hearted and many times, just straight up silly.
I completely recommend it but you must watch with an open heart, to fall in love with nam soon, hee sik and ryi o. it will bring you good laughs, heart warming moments and, just sometimes, a good policial suspense. Recommend it!

(English is not my first language)