I thought the last one was somewhat better than Song of Susannah. I do hate it, though, when an author writes himself into his own books. Clive Cussler does that (and he's an absolute crap writer to begin with).
Oh, for those who say the first book isn't all that good because it was early in King's career, The Stand is from the exact same time frame, and it is a masterpiece of character development and storytelling.
What REALLY fascinated me, though, was how King evolved this entire series so that it was, essentially, the Grand Unification of virtually his entire body of work, even the most oddly disparate works have shared characters, themes, events, etc. I thought that was not only immaginative, but rather brilliant.