Originally, I was going to give "Nabari" a bad review. The first half of the series isn't very good. The art is sketchy and rather bad, the characters are shallow and wooden, the story moves so very, very slowly and makes little to no sense, and the relationships form out of thin air. The mangaka doesn't really use the beginning to lay the foundations of the story as much as she could. She just throws the reader little pieces and drags out each chapter as much as possible. The anime only covers the first 5 volumes of the manga, and as so, is pretty bad. I was seriously disappointed and I wasn't going to finish reading the manga. I decided that I had to read the whole thing in order to form a proper opinion of the series. I'm very glad that I did.
Most of the things that were wrong with the first half of the series are fixed in the second half. The art becomes gorgeous, the characters get fleshed out and their motivations are explained (this happens in the last few chapters), and the story is explained in greater detail. "Nabari" is one of those series in which everything moves very slowly until the last few volumes. Everything becomes clear at the end.
I do wish that the mangaka had worked harder in order to grab and keep my attention in the beginning of the series. I had to force myself to keep reading, and that's bad. Also, I still don't understand why some of the characters became so attached to each other. Some of the relationships are so intense that it feels like they're entering shounen-ai territory
(I don't want to get into an argument over Yotei's sex. He was born with both male and female organs, but is predominately male. He lives as a man and Miharu sees him as male. So, for all intents and purposes, he's a man. Gao and Raiko are both male as well.)
I'm not sure if this was intentional. It doesn't bother me, but it may bother other readers. More explanations in the beginning would have made the story and character relationships work better for me.
Over-all, I'm enjoying the series. I'm current with all the chapters, and things are moving very quickly. I think "Nabari" is reaching its end, and everything is coming together rather well. I'm very interested to see how the story will end. I'm giving it an 8 because the last half is good enough to make up for the first half being so bad.