[Magin]

My opinion- there was only one thing wrong with the manga, and that was at the very end:

Spoiler for Black Cat final battle result:

When Train faces Creed for the last time, it seemed like he relied upon the spirit of Saya just a little too much. Sure, by the end he was finally able to move on, but he fell to the problem of most heroes: he became too nice, and let the bad guy live (even if that did keep a certain pairing alive). Even though i doubt there's going to be a sequel to black cat, I think train or someone would find out why it's a very, very bad mistake to let the final boss live... well, either that, or I wanted to see a little more of the Black cat in him.

and the anime... well, I haven't seen much of the anime to draw any conclusion