After the initial Pulse scene, it went a little slow for me and I picked it up several times and then stopped reading several times before committing to the book. However, once the group really starts moving, the pace is steady and each scene in the book serves to move the story forward. I liked the characters a lot. I thought they were crafted well to make them instantly accessible and meaningful to the readers.
I'm a huge fan of the ending. I'm better with open ended endings with SK than with some of his explanations in other books. I've had more than one experience in which I found the actual ending to be a letdown. For me, SK creates such scary, suspenseful atmosphere that once the climax hits and all is explained, I feel deflated. Cell did not let me down, however.
And I really liked that toward the end Denise calls to St. Anthony to help her find something lost. There's no doubt in my mind that this is a reference to Tony from The Shining and Doctor Sleep, who helped Danny find lost things.