I just finished the entire series, and overall I am fairly impressed. The only complaint I can see, which exists only when looking at the entire series as a whole, is that some of the connections between the story arcs are at some point lost. For instance, they show train's mentor at the very beginning of the series and then, without explanation as to why or how, bring him back in the final episode. There are other connections made that seem less than pristine and a little forced. I've come across this before, and the problem came from attempting to jam too much into a short tv series compared to the length of the Manga series. I have not read the Manga, so I cannot vouch completely. Overall, I was impressed with the series, although I wish I would have read the Manga first, as then I think the series would have been more enjoyable.