When I was a kid I was told by my parents not to read them. I believe it was mostly because they had heard bad stuff about them, which was hearsay and largely unfounded.
I watch the goosebumps tv show on youtube and find the stories very original and imaginative. If you are an aspiring horror writer you could learn a few lessons from R.L. Stine.Now before you start thinking I'm someone with Peter Pan syndrome and that even though I'm 21 I don't want to grow up, let me assure you that is not the case.
I just happen to enjoy the stories often times, while some people may consider them elementary fright novels, I still think R.L. Stine is a very gifted writer. Some people may consider his writings for children and teens, but I believe, from personal experience adults find them entertaining as well.
Some of my favorite goosebumps tales are "Monster Blood","Piano Lessons Can Be Murder","The Haunted School", and "The Ghost Next Door". If you have never read the Goosebumps tales let me assure you they are worth your while.
With that said go check them out, you won't regret it.