It reminds me of Yu-Gi-Oh! and Shaman King - shows I watched when I was about 13 and really enjoyed, back then I didn't even know what anime is and I'm no sure I was even aware of the shows' origin, but I still enjoyed them.
I picked MAR for the sole reason to relive that excitement and since it had 102 episodes I expected to have tons of fun with it, alas, the reality was different.
The show started well, the premise of the main character being transported to a fantasy world he has longed for was interesting. The first few episodes, where he still figures out what goes on and characters are being introduced were the more interesting ones for me.
After that, the majority of the show is about a tournament, but that's where I started skipping just to get through and say I've finished it.
The story on paper sounds fun, but in reality it's really mediocre and poorly executed, very predictable and uninteresting.
The art style is OK, I can't say ti was bad, but it wasn't anything remarkable either, many characters shared similar features, like color palettes and such.
I think the show, like other long running ones suffers from recycled sounds to the point where it becomes noticeable, not a deal breaker, but just one more negative to the list.
The characters were extremely poor developed and suffered from "Anime Humor Syndrome" - a grave disease where one would fall in the same absurd situation over and over and react the exact same way without ever noticing it, the worst part of this disease is that it spreads in the air and it's very infectious, by the end of the episode, every other character would have contracted it.
After passing the 41st episode, I found it really hard to enjoy it and decided to fastforward just so I can say I've finished it and not dropped it, I really wanted to see the end without losing track of events.
Overall I both regret wasting my time with it and I'm also glad I know what is it about so I won't have to bother with it again. On a positive note, I think that if I was 13 again I might've enjoyed it A LOT more.