I'm not sure what the previous reviewer had to say (unfortunately I don't speak, much less read, Japanese), but I have to say that I enjoyed Jumper (and it's sequel, Reflex), very much.
The story centers around a boy who discovers that he has the ability to "jump" or teleport, and how he learns to deal with his newfound power. Life's not all that easy however, since his father is an abusive alcoholic, and his mother has disappeared long ago. However, if things were all happy and fun, there wouldn't be much to read about, would there?
We get to see how he matures over the course of time, how (and the reason why) he chooses to use his ability, all the while trying to make sure that others won't manipulate or otherwise take advantage of him.
Overall, the book is very enjoyable, with a few minor gripes. For one, the protagonist is really incredibly smart for teenager. Not that teenagers can't be that smart, but sometimes he just seems a little too clever. Also (and this is not necessarily a bad thing, but more of a warning for parents), the story at least once strays into areas that contain just a twinge of adult-oriented themes. None of it is gratuitous, and it actually deals with a very real fear for parents nowadays, but (for example) attempted child rape is not something that kids need to be reading about. Again, I emphasize that nothing is put in there for the "shock" value, but that I would not present this to children who aren't at least in their teens. I could also potentially gripe about the physics involved in teleportation, but honestly, it's plausible enough for me as I'm not one to look too deeply into the science of a SF story.
None of the above are major gripes which is why I still give it a full 5 stars and look forward to the other stories in the series! (on a side note, the movie is coming out soon, but I'm still uncertain what I can expect from an adaptation..)