NANA is definitely one of the best mangas that I've ever read. There's something about it that makes it very different from other ones, so I personally think it's a must-read. Anyways, my review may contain some spoilers, but I'll try my best not to reveal too much.

Story- 10
The first thing that comes to mind when I think of NANA is how incredibly realistic it is compared to many other mangas. It starts out very normal like any other shoujo/josei manga; introducing the two main characters who both happen to have the name Nana. It pretty much follows the life of these two girls as they meet on a train to Tokyo, and then later decide to share an apartment. It may sound a bit dull and boring, but the story always draws you in and makes you wonder what would happen next. Personally what I think is best about the story is the realistic aspect of it, since I've always loved serious and realistic mangas/animes. After reading so many silly mangas with unrealistic story plots, I found it very refreshing to read something completely different. In fact, it's so realistic to the point that I find myself wishing that it wouldn't be so realistic, since NANA definitely isn't your happily ever after story.

Art- 7
Well, I hate to say this but the art of NANA isn't the best. It's not that the mangaka is a bad artist or anything, but the style of NANA just doesn't appeal to me very much. I also don't really like how some of the backgrounds seem as if they are a completely different style of art. Sometimes it looks as if the characters are standing in front of some wallpaper rather than in the actual place so that kinda bothers me. On the other hand, I love how much detail the mangaka puts in the characters and their clothes.

Character- 10
I'm not giving this section a 10 because I think all the characters are perfect and love them all to death, but rather because there is at least one thing I don't like about almost all the characters. That may sound weird, but the reason why I like it is because of how realistic it makes them and how it makes you able to relate to them very easily. I can easily imagine all the characters being real people, and almost all of them are very well developed. Another thing I like about the manga NANA is how the mangaka isn't afraid to put in traits like selfishness and possessiveness and have the characters realize those traits in themselves. I don't think I've ever read another manga that had that, so I was pretty impressed when I first read those parts.

Enjoyment- 9
I really don't have much to say here...all I have to say is that I thoroughly enjoyed reading this.

Overall- 9
Okay, I'll just be repeating myself here if I say how much I enjoyed it, so I'll just add a few things here that I didn't put up here. So another thing I like about NANA is how it makes you think a bit about life in general. The things that the characters say sometimes made me realize some stuff, and now because of NANA I think I can understand people a bit better. :3

Recommendation-
I recommend this manga to people who like realistic plots that have a bit of humor in it. But if you're someone that likes fairy tail plots, happily ever afters, perfect princes/princesses, or couples that have no problems then this definitely isn't the manga for you. And it's also for an older audience so please don't read it if you're really young. o3o