Pokemon Black and White

This series was the worst of all the anime series we've seen. A lot of it should be attributed to the poor management of the story and characters.  

Pokemon Orange Islands

Even though it is placed second from the last, this was much better than Black and White anime and it was also the series where Ash won his first major title. 

Pokemon Johto Journeys

This was a very crucial series because this is where we started to see major development of Ash as a character as well as a Pokemon trainer. 

Pokemon advanced

The heat turned up a lot in this series as we were introduced with frontier brains who were tougher than any gym leader Ash ever faced. 

Pokemon sun and moon

Ash captured some of the rarest pokemon. This made his team to be his strongest regional team ever. He even became the champion of a region, redeeming himself. 

Pokemon journeys

It had the potential to be the best of all. It doesn't change the fact, though, that it is great and the first instance ever of PWC, featuring the contest of Champions. 

Pokemon Diamond and pearl

There is almost nothing that you couldn't like. The rivalry of Ash and Paul was the feature and the most unforgettable of all was the legendary defeat against Tobias.

Pokemon xyz

It is the best series so far in terms of great battle music, animation and intensity. The storyline was pretty good as well, but the main feature was the Ash-Greninja.