I honestly don't know what to say about this one that hasn't been said countless times already, but I'll give it a shot.
Despite its anime adaptation's less than stellar reputation, this manga truly is something to marvel at. The story is incredibly well-crafted and captivating, often surprising me with revelations about their world 400+ chapters in that completely change how I view events that I've known to be a certain way for so long, and yet rarely does it ever feel forced or unnatural. Almost everything feels planned out perfectly. The only part where I feel the progression is a bit unnatural was the beginning of the very last story arc, since it kind of feels like Kishimoto had no idea how to defeat the main villain.
My only other notable complaint story-wise is the lead-up to the Fourth Great Ninja War, mostly because it introduces a barrage of new characters from all different villages a bit too quickly, and because neither Naruto nor Sasuke are present for a dozen chapters at a time to keep the character dramas pressing forward, causing the story to slow to a crawl for a bit. However, only having two complaints from 700 chapters of content more than speaks to the value of the writing.
The world building is absolutely fantastic as well. From the minute details of chakra (superpower life force of the week) control to the entire history of the shinobi (ninja), this world feels almost like a high fantasy in how incredibly rich and detailed it is. Any time a new piece of world building came up, I could barely tear my eyes away from the page.
While the overall plot is fairly simple (save the world X number of times), it's the characters that truly drive this story forward. While sometimes too simplistic in his ideals, Naruto himself has grown to be one of my favorite shounen protagonists, will his undying will and pursuit of his dream becoming damn-near awe-inspiring in the latter chapters. He also becomes the prototypical example of an outcast youth striving to prove himself and gain the acceptance of his peers, and watching his journey from orphaned punk to savior of the world was absolutely incredible. The pain that he felt at his absolute lowest moments is so palpable that I actually cried a little bit.
As for Sasuke, I've gained a huge appreciation for his character by switching from the anime to the manga, as the full weight of his incredibly dark and depressing situation is much more focused and poignant. His path to revenge is one paved with hate, deceit, and breaking of bonds, and his descent into darkness is quite compelling. I actually cared when he did the wrong thing and strayed from the noble path, and, at times, I almost agreed with his actions because of his motivations, even when those actions were rather horrendous. My body shivered at the absolute dread that he experienced through his years of suffering, unwanted revelations, and growing malice towards what destroyed his once happy life.
Because of how exceptionally well-crafted both Naruto and Sasuke are, the way they play off each other is just a tad shy of writing genius. Their conflicting ideals and differing backgrounds shape them into perfect foils for each other to grow off of and inspire surprisingly engrossing debates of what makes a true shinobi.
I could go on for days about the rest of the cast, but I think it will suffice to say that there isn't a single character that I adamantly dislike. I will say though that Kishimoto's genius does shine through in his foils and reflections of Squad 7 (Naruto, Sasuke, and Sakura) through the generations of past shinobi (The Legendary Sannin, Kakashi's squad, and Pain's group in particular), and by slightly altering the events that happen to these characters, it creates drastically different outcomes for the same character archetype and spawns a character study that almost feels like an academic study of character development at times (in a very good way).
The artwork, while not the most richly detailed or awe-inspiring that I've seen, still manages to be not only consistent and pleasant to view, but also decisively unique amongst its shounen peers, from the different designs of eye jutsu (techniques) to the Tailed Beasts that terrorize the ninja world. Unfortunately, once again, I must complain about a shounen manga having unclear and cluttered action scenes. It doesn't happen all the time, and when it's clear what's happening, it's extremely compelling, but when the frame gets filled to the brim with different actions and jutsu, it's almost impossible to tell what's going on.
Overall, Naruto has been an absolutely fantastic read that I highly recommend. However, I also realize that I do have a lot of complaints about the series as a whole, and it caused me to question how high to score this series.
Then I asked myself: do I want to go back and reread it right now?
...
Yeah. I think I do.