This review will focus on the strengths in One Piece over other shonen manga and provide examples to support them, but less so on weaknesses in One Piece since they seem to be pretty obvious among the experienced manga readers.

First of all, characters. One Piece provides a strong cast of main protagonists with emotional backstories and unique characteristics. Each member in the crew doesn't overlap each other in terms of personality, appearance and abilities. Now you may think that is a common trait in all popular shonen manga but there's something different about One Piece.

There's consistency with the characters. Oda doesn't randomly make punchlines with his characters. The punchline is usually related to one's backstory. Usopp tells lies because he wanted his mother and people in the village to be happy; Nami loves money because she once had to steal money to save her people; Chopper loves when people praise him and he can't hide the pleasure when he try to because he has very low self esteem and refuses to befriend with others due to his trauma. He believes in everything Usopp says because he lacks life experience; Brook keeps cracking jokes because he had to keep lightening himself before he went insane when everyone in his crew died.......etc. It offers so much nuance to the characters when Oda put these comedic moments here and there.

Don't get me wrong. None of these character traits is exceptionally subtle. But when it comes to One Piece, it works incredibly well.

It is a manga with more or less the same main cast the cast only adds people but generally doesn't drop people. (If you don't count Vivi or Jinbei who didn't officially join.) This provides One Piece with a strong advantage. Oda can give a lot of nuance to the characters. While they go through different adventures, they react a wide range of different ways. Whether it be a escort mission of a ordinary, warm-hearted princess to her own country, a fantastic journey to the sky island or a slump of the crew where people leave for the greater good or for a small quarrel, strawhats seem don't run out of ways to interact with each other and with their adventures. This makes the cast incredibly fun to read. Also, Oda adds new members to the crew to keep the character dynamics among the crew fresh and fun. His wacky way to portray the characters fit perfectly with the vibe of the story.

Though One Piece suffers from a formulaic way to characterize new members by having everyone a tragic backstory in a flashback, the character development in the main story is interesting enough and their flashbacks are effective enough to make the characters work.

Next, let's talk about the story. It's obvious that the main protagonists are supposed to be unstoppable. Every arc it's very clear that strawhats would beat the villains and the conflicts are going to be resolved at the end of the arc because the story is progressed by having strawhats travelling to different places and meet new people and opposing forces. The same villain won't stick around for a long time. But One Piece is less about who's gonna win and rather focuses more on how they inspire people they encounter to fight for their lives and dreams. Though every arc follows a formula of strawhats meeting new people, knowing their lives suffer, then fighting for them. Lots of arcs tell a different story with a different theme with alasbasta being an escort mission, Jaya being how should men fight for their dreams, skypiea being a romantic story between two men, Water Seven being a romantic story between comrades by the disobedience of the tyranny etc.

The story does repeat itself after time skip. All in all Oda is still a human being, he runs out of ideas.

The art is probably the weakest aspect for One Piece. While the fight scenes feel powerful, the way Oda design the panels lacks fluency. From time to time when there is too much stuff in the panel, the drawing feels messy. The color covers are really good but they aren't related to the story.

Overall One Piece is a really exceptional manga for romantist who is looking for a story about friendship.