The No. 6 manga is the only thing from what I've encountered so far that I've been able to give a 10 to. I'll do my best to refrain from any spoilers or summarizing the plot.
Story. (10/10)
The Good: the plot is excellent and I thought it was extremely well paced. From the very first page you're transported into the fake world of No. 6. You're then taken for a crash course on reality in the Western District. You're swept away by the every line, every detail on the page.
When I first saw the anime, I was jaded. When I read the light novels, I wept. It wasn't until I read this manga that everything felt complete. The execution of the plot was perfect. There was never a dull moment for me and I couldn't stop reading. In the end, everything came together in a way that exceeded every hope and every desire I could have had.
The Bad: I spent quite some time trying to come up with something to complain about when it came to this manga, something-anything- that irritated me. I found...nothing, much to my own amazement.
Art. (10/10)
Wow, that art. What can you really say? The art was simply mesmerizing. You weren't just reading a manga. You were there. You were living it. Facial expressions, body language, backgrounds, panels, and bubble placement- it was all perfect and easy to follow. More than that- the art of the characters themselves were flawless. More often than not I found myself taking quite some time per page just to really appreciate the beauty of the characters and the fantastic details. I can't find a single thing about the art that I'd change.
Character. (10/10)
This is where the manga shines brightest. The struggles of these characters are real. They've all been shaped by their experiences, and oftentimes not for the better. You end up at the edge of your seat with baited breath watching as these characters are forced to make decisions and how those decisions are going to effect their personalities. The more you learn, the more you eagerly wonder what will happen next.
With that said:
This manga does feature two 16 year old boys who are romantically attracted to one another. It is this relationship, this friendship, this bond that makes the story great. This manga is not about a gay couple having gay sex (which they don't, by the way). It would work just as well if Nezumi or Shion were a female. I love that it doesn't stereotype gay relationships. It shows two people who find each other against all odds and dares to take charge of their own lives.
Quite frankly, I don't think people should freak out over Nezumi and Shion's relationship. If you chose not to read the manga because of that, I certainly can't stop you, but if you like an amazing dystopian manga with lots of action, and character development that makes you think, then this isn't one you should skip over lightly.
This is about two boys, as different as night and day, who form a seemingly impossible bond and change everything. In their own lives and in the world around them. It's a story of personal growth. To be a ignorant or to be knowledgeable. To be conquered or to be the survivor. To be human or to be...something else. It's a plot driven by characters evolving and it's utterly amazing to behold. In light of that, so what if two boys like each other? It's their relationship that makes the plot all the more worth while, and every decision they make so much more intense because of how they force each other to change.
4. Enjoyment. (10/10)
I am enthralled with every single aspect of this manga. It glides effortlessly through the pages, engulfing you in a world of horror, action, despair, and hope where hope should only be done while dreaming (if even then). It makes you question what you'd do if you were in any of the characters' positions. How far would you be willing to go for someone else? How much horror can you see, hear, smell, touch, before it becomes a part of you? How deeply can you change, before you lose yourself completely?
You are put on a roller-coaster of emotion and the ride doesn't end just because the manga is over.
5. Overall. (10/10)
This was, quite simply put, a very outstanding and unforgettable manga. In fact, the only thing bad about it is that it ends.