Since everyone else is posting opinions.
I like Yu-Gi-Oh (second series. Haven't watched the first series except for small clips), mostly because it's amazingly funny how the rules are broken, and it's also a pretty cool story and stuff. and the Abridged series ;D
GX, I kinda dislike. It's seems more like a cartoon rather then an animu and stuff. The characters look and act childish and I lost interest in it pretty fast. They didn't even have a Lightsworn character. Also, it seems like the black sheep of the YGO family. The hair isn't eccentric, there's no real "villan" that is defeated (but they become friends or fuse souls with Jaden or something), and it's just weird ;~;. What a terrible series. . . except for Alexis Rhodes. . . >www<~ unyuu~
5D's has to be one of my favorites. Not so much because it's CARD GAMES ON MOTORCYCLES, but rather because it's a pretty good storyline with a pretty good plot. It's silly and dorky like the other Yu-Gi-Oh! series, but it's pretty badass also, and they don't bend rules that much. Except that Yusei cheats like an asshole. Nobody gets 5 tuners for Shooting Stardust. Nobody. Unless they're cheaters. And Sherry is moe too >w<~, but apparently nobody knows who she is. She's French. (also hyurp derp I like the one YGO Abridged episode~)
ZEXAL (aka CARD GAMES IN SPACE), from what I've seen, looks kind of absurd. The animation style is back to the childish sense, where the scenes are bright and colorful and the characters are all colorful and eccentric and 13 and stuff. Yuma pisses me off intensely, though. He's stubborn and he's a terrible duelist and his hair is terrible. He's like a beetle or something. The only thing good about ZEXAL is Cathy >w<~. . . and Astral. Astral is pretty cool. I find him sexy kind of, because you know, he's a feminine-looking naked ghost man, but once I found traces of testosterone, his sexy level kinda went down. But Cathy >www<~.
tl;dr 2nd Series and 5D's are cool. GX and ZEXAL are too childish for me. They're probably good for the younger audience, but just not good in my taste ;~;.
