I liked this movie. For a horror movie, I thought it wasn't too bad. Maybe it's just me, but I find that a lot of horror movies have really weak story lines and have a great potential for switching to the gore aspect. 1408 is more of a pyschological thriller and is not overly gruesome at all, like most pointless horror flicks are.
If you're the type of person that gets bored watching a whole movie take place in the same setting, then this movie is probably not for you. It's more of a story that plays into the creative and imaginary mind, and leave it to Stephen King to harbor that creativity in a dark place. It's a story that indulges in the "what if" and "can it get any worse" concepts in a supernatural sense where there are no limitations. John Cusack has a standout scene in this film, where he is forced to relive the loss of his daughter. I loved his acting in that scene -- pure, raw emotion. He must've been digging deep in that one; incredibly heartfelt. I was not expecting that.
Watch the movie if you like a psychological twist in stories, paired with a creative plot element.