It's been 5 years since this drama came out, and still there is almost nothing that compares to the magic of NIF:
- a focused, structured story that is well-paced, doesn't have any filler content, and also doesn't think of its audience as idiots
- strong, intelligent characters that are unique and lovable (or at least understandable), both male and female, with character arcs that go somewhere and feel earned
- natural, expressive acting where you feel the full personality and history of each character
- beautiful costumes, settings, and scenery as befitting a historical/costume drama

NIF has the clear elements of good narrative storytelling, which seems rare in dramas nowadays - setup, rising action (with each step a necessary piece of the plot and building up the tension), climax, and resolution. Most other dramas that I've seen fall into a trap of just having things that happen one after another, with nothing to link them together and no clear advancement or tie to the plot = it's less a story and more just a series of events.

The only criticism I might have of NIF is that I felt the resolution was a bit rushed, but otherwise this is the drama that I measure all others by, and the vast majority of them fall short.