Much better than I expected, to be honest. I LOVED the idea of setting a fantasy quest type of story in what appears to be a post-apocalyptic nuclear desert waste world.
Other than that, the writing is simple and straightforward. It's still too soon to analyze character depth (which is, in itself, a surprise: Stephen King isn't shy about using shallow and charicatural characters and making sure you know that, and what to expect of them, from the start).
Highly enjoyable, can't wait for the next one.