I read the second one and thought it was pretty good.
I read the third one and thought it was ok.
I read the fourth one and thought it was excellent (the backstory parts were, anyway).
I read the fifth one and thought it was stupid. (I mean, come on: robots dressed like Dr. Doom carrying lightsabers and exploding Harry Potter snitches?!)
I read the sixth one and thought it was even more stupid. (He put HIMSELF IN THE BOOK?!?!)
I read half of the seventh one, and I just couldn't take any more. I did skip to the end, so I could see how the series ended (I would've hated to have put all that time into a series to not know the ending), and I literally tossed the book against my wall. I thought the ending was one of the worst endings in the history of bad endings.
At that time I made a vow never to read another Stephen King book again. Those are many hours of my life that I will never get back.
Curse you, Stephen..........curse you...........
At least now I've learned how NOT to write a fantasy series.