Creative, albeit haphazardly executed TV series
I'm just going to be completely transparent - I've only read some of the books in the range, and rarely paid attention to the show when it first aired on Fox Kids. I've only started watching it as a teenager, that is, after I finished watching Are You Afraid of the Dark.
I can honestly say that in comparison, Goosebumps just isn't that great. Some episodes just feel incredibly rushed, especially the twist endings.
There's one episode where these kids live their life normally but are really supposed to be dogs. How can dogs become so adept at living as human kids, to the extent of forming a rock band? In another instance, this kid goes to camp and is put through a series of tests and trials, but then it's revealed that he was part of a government experiment, and he and his parents seek Earth as their next destination. This is regardless of the fact that the campsite and all of its happenings were very much on Earth - way to merely tack something on at the end.
Speaking of endings, I've seen one of the reviews say that "the good guys 'always win' in the end". Yes, they 'win' plenty in Are You Afraid of the Dark. But in this series, they don't - not even remotely. No ending in Goosebumps is positive. Often, the main character/characters find themselves trapped, about to be killed, or subject to a bizarre, abrupt cliffhanger. This can be especially unsettling to younger viewers, particularly those who expect a happy ending.
For this reason, I'd only recommend Goosebumps for those a little older, who could appreciate it from a creative standpoint. Otherwise, it may have a longstanding ill effect on kids aged six and below.