The comic changed writers after the seventh album. Whether the next albums are still enjoyable stories or inferior to the original ones is a bit of a touchy subject. This wasn't helped by the fact that the storyline of the series was pretty much finished in the sixth album, and the eighth one served as a reboot of the series with the familiar characters in new adventures. This died down a little when the ninth album was released, as it demonstrated that the new writers could come up with some good and interesting plots as well.
The seventh and eighth albums in general are the ones that spark the most discussion because they are little more than collections of stories and, in the case of the eighth one, also a rehash of some of the older stories. They are not considered terrible, just much more weaker than the older ones and the ones that follow them.
Growing the Beard: Many who read the albums seem to agree that this happened starting with the fifth album, where the story and the atmosphere got much more darker and with many twists.
What Do You Mean, It's for Kids?: Pretty much the reason Billy's origin was changed in the cartoon. The entire premise is about a child getting killed by a car and reincarnated as a cat. There are also some occasionally scary parts, including animal experiments and, when Sanctifer is involved, animals getting killed.
Show-specific YMMVs:
Badass Decay: Sanctifer goes from a huge, frightening, villainous tomcat to a bully that is never that much of a threat and becomes reluctant friends with the main cast.
Broken Base: Is the series fun and enjoyable in its own right, or a very poor and messy adaptation that cannot even compare to the comics? You decide. It didn't help the fact that many things were changed for it, and both its stories and its atmosphere were quite toned down for younger audiences.
Fridge Horror: So Billy is gonna be a cat for the rest of his life?
Moment of Awesome: The episode "A Star is Born" features Mr. Hubert being taken by a pet food maker to be used as a mascot. When Sanctifer arrives in the junkyard to claim Hubert's Cadillac as his own residence, Billy tries to put up a fight against Sanctifer. Sure, he's technically a kitten, and judging from that scar on his face Sanctifer is a veteran of many battles and thus Billy loses but the kid's got guts.
