Before saying anything, I wathced it with a Finnish dub.
This is a series I have huge nostalgia on. So I don't even try to be objective.
Story
While the story might not be the most unique (the boy wants to be a Duel Master just like his father before him blah blahblahblah), I find it still quite charming. While this is mainly the story of Shobu trying to fulfill his dream, I feel like the plot isn't even main point of this series. It has weird plot holes, sure (why did Hakuoh start looking younger suddenly, who Knight actually is and how the heck this 12-year-old kid is attending death battles with his parent's permission) and sometimes characters are making really dumb desicions (well of coooooourse we needed that clichéic "the main characters start arguing and the gang is about to fall apart episode"), but I find it still most of the time interesting.
Also, this is not a copy of Yugi-Oh.
Animation
While most of the people will probably find the design of the creatures almost eye-hurting due the old CGI, I thing it still has it's charm. And since it's only used to animate "the creatures" (the card thingies basically), it really makes it feel like they come from another world (oh right, they also used it to animate Rekuta's weird flying in the air sessions couple of time (I really suspect they added those parts in the US)). Other than that, I feel like the animation looks actually pretty good.
Sound
The music used in the background is mostly quite basic anime-level and I would be interested to see the original JApanese version some day to see, if there's any differences. But nothing too weird, really. Except the musical parts.
Oh, the musical parts.
Seriosly, this at least must be something they added in US. In couple of episodes in the end of the first season, characters starts randomly sing (even Kokujo, even our cool edgy angst bad boy emo cool man Kokujo, has a hecking polka song). IT stupid, it makes zero sense! And I love it. It is so stupid, that it feels some sort of fan-made parody. And that's always something I'm eager to watch.
And then comes the dub (Finnish dub)
It's gold. Just pure gold.
This is probably one of the funniest dubs I've ever heard. Imagine this: A dub that contains all the popular culture references and fourth-wall breakings possible. This series has references to Finnish TV dramas, main stream movies (Titanic, Lord of the Rings, Harry Potter etc.), celebrities and all sort of stuff like that. Also "Did I just imagine or did that commercial break take a week." The voice acting is also hilarious, even though there isn't always that much credibility in their acting ("Shobu. Shobu. I won't forgive myself if you don't wake up. *monotonic sobbing*"), but even at moments like that it's ironically good. Also Kokujo's and Hakuoh's voices are just perfect, Kokujo's voice is just a perfect edgy adult man voice and Hakuoh's voice is probably one of the few "pretty boy" voice's I can name from this country.
Characters
This series is just a bunch of meme character. We have the clichéic shounen main character, the smart shortie sidekick, the boring girl, the athlete girl, the pretty boy boy with existential crisis, the emo man, the mysterious, dark and handsome but at the same time extremely self-ironic and goofy mentor (with zero navigation skills), the mad professor, the weird man-baby (just what the heck Boy George even is!?) and that weird character with funny look and zero point to the series (Kintaro). I love them all. If this was a popular series, Kokujo would have all the fans (alongside with Hakuoh the Pretty Boi), people would make Knight memes and think Mimi is badass. I see so much meme potential with this show that it's almost a crime no one talks about it!
Overall
Even with clicheic plot and all the other issues, this is a good serieswith meme potential and funny characters. Please give it a chance. And for the last time. IT is not a Yugi-Oh copy (no hate for Yugi-Oh, I do believe it's a good series).