gp1974,
I think it depends on your current level of preparation. I found the geometry book to be very useful as well as the number properties and word translation books. These books cover all of the topics that you need to know cold. They are more in depth than the Kaplan books and show some of the common tricks. However, a lot of the material that is covered in the books can be found on testmagic, it is just a matter of sifting through the site. In summary, if you want a very consice set of notes to review and have a few extra bucks to spend it may be worth it. I hope that helps, Best of luck.