Yu-Gi-Oh! Zexal

The previous Yu-Gi-Oh! anime series suffered from plots going completely absurd at times, especially in the first one, not to mention all the filler episodes that add nothing to the plot (looking at you GX). Zexal does not have these problems since the plot is fairly coherent and each episode feels like it fits well with the rest. It's visually good and the character design is captivating.

Now the most important part in the whole deal is the dueling itself and how the cards are played and presented. If you like the card game, then that's what really matters anyway, and Zexal has some interesting and intense duels. Of course the main course here is XYZ summoning, along with the cards that make it possible to achieve, and if you're playing Duel Links which introduced it recently, then you'll gain a lot of insights about it by watching.

The only thing I find annoying is how bad at dueling Yuma is, the protagonist, sometimes (unlike Jaden for example), but I understand it was a necessity to justify his bond with Astral and show how acquiring number cards can make you stronger.