I have reread this manga multiple times and each time I've enjoyed it. I would rate 70% of this story as a 10/10, though there are parts of it that make the story drag on. Since the majority of the story is amazing, it's easier for me to list the story arcs which I might rate a 6 or 7/10. Those are: Nakai drawing in the snow (ch. 37-38); Takashi's romantic drama (ch. 61-66); Tanto and +Natural serialization meeting (ch. 67-72); Iwase rivalry (ch. 94-99); Takagi and Shiratori and the one-shot competition (ch. 100-113); Nakai drama and the class reunion (ch. 128-130); Nizuma's first-place run (ch. 135-140); Nanamine's return (ch. 141-149); and the hot springs trip (ch. 162). If I could boil down the problems with these sections to one idea: characters act in unrealistic and at times uncharacteristic ways, leading to drama that likely could have been avoided if they had acted as one would expect normal people to act.
At its core, this is an inspirational manga, showing two friends dedicating their lives to achieving their dreams, taking a gamble on the chance of making it big creating manga. Of course, this type of story is captivating precisely because it's not something I would ever wish to do myself (Why choose a risky career? That's what hobbies are for.), so I enjoy living vicariously through the characters and watching them succeed. Of course, the authors realized this and made it a feel-good story, a story where you can tell from the very first chapter that their dreams are going to come true.
There are a decent amount of characters that show up throughout this manga, and a large percent of them are captivating and unique. Many times--like with Eiji, Hiramaru, or Miura or any number of other characters--whenever they are first introduced they are drawn slightly differently from the look they eventually settle into. It's only noticeable when rereading it, because as the artist continues to draw the characters they seem to become more comfortable with the core of the character. The art is exceptional. The artist draws normal people (some based on actual people), but with a sense of flair and pop, exaggerating the fluidity of body parts and movement to turn it into something which could only be done in manga, as Eiji Nizuma would say.
One of my favorite scenes involves Takagi talking about how manga artists who are able to draw everyday activities in a captivating manner are geniuses. And while Takagi's sitting on a couch saying this, Mashiro's in the background pushing a broom around. I think this is hilarious, but it only works because it's asking the reader to break the fourth wall and recognize that the authors are calling themselves geniuses. This manga wants its readers to analyze it and think about how it was made. By discussing the behind-the-scenes processes and tactics of manga creation, it expects to be read with a more critical eye. And for the most part (obviously barring the story arcs I've mentioned above), this manga stands up to scrutiny as well put together.