I've never seen a series of this magnitude take such a risky and ultimately ingenious way of telling a story as showing it through a lens of a character. Some things in the story can even be disregarded completely as they could just be happening in the head of Araragi. It still succeeds in keeping a very slow pace very interesting, which is no small feat. It also keeps you on your toes, as you cannot know exactly what is going on.
Art: 10
Why? Because it perfectly fits the mood, music, and most importantly, is composed from more than just pictures. It's made from the very mind of the character of Araragi. From the touches like every car, every bike (excluding Araragi's own) looking exactly the same, to the big ones, like the absolutely empty city, it all enforces in a brilliant manner the way Araragi sees the world. Sometimes there are even absolutely pointless things on screen, but that's why it's brilliant: We all see and think about pointless things in one point or another. Also it's surreal nature makes it very interesting to look at, and it really keeps your attention.
Sound: 10
I simply love the soundtrack and the sound design in general. The characters' voices are spot on, and the soundtrack is always more than fitting. It's the kind that is enjoyable to listen on it's own, but almost transcending when shown with the brilliant artstyle and the real and surreal scenes the story takes place on.
Character: 10 (Would give more if i could)
Even if Araragi was the only character to rate, it would be a 10. Character portrayal is rarely seen to be so integral to a series as in Bakemonogatari. Bakemonogatari takes the simple idea of taking the idea of portraying the whole series through a lens of a character, and nails it in every possible manner. It makes the surreal scenes realistic, and adds mystery even to the most normal of occasions.
Enjoyment: 10
Normally it would be only 9, but when I realized that by a small change in the point of view can change a series an insurmountable amount, I started to enjoy this series on another level. It feeds my brains with ingenious subtext and never is too greedy with it's execution. It consists, mostly of dialogue, but it never feels dull, as the conversations are real in a surreal sense, giving it a rarely seen depth.
Overall: 10
Ultimately the best series I've watched until now, as it makes dialogue more interesting than action, and makes action and dialogue both an abstraction.
It may sound hard, but believe me. Once you realize the way to watch the show as I think the makers intended, it makes the whole package stand out from all other series.
