Well, a Stephen King classic, that's for sure. The characters were nicely portrayed and their development was believable enough. Especially some of the major characters, like Larry Underwood or Fran Goldsmith, and Harold Lauder. Somehow the "enemy" Flagg was not as impressive and memorable to me than others made me believe, that was a tad disappointing.
The book is about a post-apocalyptic America after a plague wiped out the majority of the planets population. It is a "Good vs. Bad" story line, which sometimes (unfortunately) drags a little during the second part of the book. While the post-apocalyptic problems that the people left behind have to face are drawn very realistic, there were too much pages "wasted" for depicting a specific character development (repeatedly) [can't say more because of spoilers]. Overall it is a human story, with a good portion of religion, faith and destiny put into the mix. It shows the best, and the worst, humankind has to offer.