The problem with K is the lousy way the story was told. K could easily have been done better, so what attracts the viewer to K is the fanservice. Neko the cat girl, the flashy fight scenes and the high production values for art and animation tend to be the main attraction in K. It's pure superficial style but that superficial style is pretty good when it happens.
Normally I would give K a 6 but it gets bumped to 7 just because the last episodes pull everything together so well. What ended up being mostly a mediocre anime with an annoying main character and awesome side characters is salvaged by the last few episodes. A lot of plot threads all happen to be revealed and then get solved in quick succession like they are coming out of a machine gun towards the last third.
If the story behind K was told better the anime could have been something really great, after watching the last episodes you'll be left neither satisfied or dissatisfied.
