Well, so far Naruto has had shitloads of plot holes, as well as Bleach. Or so I've heard.
Either way, I've seen at least the first few 80 episodes of Naruto, and they haven't been half as satisfying as One Piece. Also, Naruto has TOO MANY FILLER EPISODES! There's almost an entire season that has nothing to do with the main storyline and only add contradictions that conflict with the canon storyline, thus hampering the series as a whole.
Bleach eventually just turned into DragonBall Z with another name. When it stopped being about the different kinds of swordsmen, the anime just started going downhill as far as I'm concerned. And I've heard horrible things from people that watched Bleach (and are now turning it down) from how bad it's getting. Also, lots of filler.
One Piece, on the other hand, paces it's fillers. Instead of adding a whole bunch of extra episodes until the manga catches up, they foresee that happening and add some few filler episodes within a season. They also add more events within a canon episode and can instead focus on the main storyline while lengthening the anime so that the manga has time to catch up to it while they're still making the last manga chapters that came out.
As for the characters, Ussop is my favorite character and he's the weirdest looking. Yes, he's generally considered the comedic relief character, but he's also a character that you can identify with because he's normal. He's just like if you and me go together with a band of superhuman mofos that can kill dinosaurs with their hands. But Ussop is quick-witted and resourceful, so he does have his purpose in the crew. And he also ends up being one very fearsome dude eventually.
The other characters are fun to watch too. Luffy is always having fun or kicking ass. Tony Tony Chopper is cute-looking. Nami is always bringing conflicts regarding money, and tends to break up Zoro and Sanji who are always bickering. For some reason I find Nico Robin to be hot... and... I dunno. The story is just very well thought-out, the places they go through are memorable, the progress they achieve is meaningful (the new bounties they get basically reflect their strength, and their bounty goes up every time they beat a story arch boss).
Most of all, characters who are seen at the very beginning and are dismissed as characters that were only meant to be part of a particular part of the story can re-emerge later on with newly acquired powers, weapons or allies and become part of the story later on. No character around which there was a plot at some point is simply dismissed. They usually come back later on in the series to see what has happened to them, etc...
Finally, as for the art style... I can agree that sometimes it seems a bit out of place, but in a way it's what makes it different to the other animes. This anime tries to break anime cliches, and that's what I love about it. They make lots of jabs at anime constants. Like, someone tries to make a fancy exit with an explosion, and when the explosion clears up the guy's on the floor sizzling, etc... In a way, I think that the art style the creator went with was a way to jab at anime cliches as well. The same way people in real life don't have to look good to kick ass, the same way people in One Piece could look like garbage but be honorable warriors, or people to be feared or simply just nice.
I think it's the same reason why there are so many weird yet cool powers in the series. Think about it, the LEAST power you could think of for a protagonist of a series would be elasticity powers. There are several other powers in the series that, while sound stupid, are actually feasible in practice. One guy is the best batter in the world. There's a guy that can turn into smoke and control it. There's even a dude which's only power is to turn his limbs into springs. And yet, all of those three powers are actually extremely formidable when you see them being used.
The way I see it, Eiichiro Oda got tired of all these animes where everyone important is either 'good looking' or has seldom to zero physical flaws. He got tired of 'awesome, edgy' powers like 'controlling the darkness' or 'using obscure weaponry'. He got tired of all the characters you get to see only once and then they're gone, never to have trained harder to best the protagonist. He got tired of places that are there for decoration, which's existence might as well be null because the place has little to no impact to the storyline.
People don't have to look good to kick your ass. The geography of the world conspires against you. The characters have a purpose. They have variety.
Unlike many other animes, One Piece's world is alive.
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-looks up at the wall of text- Holy shi...! I did that!?
