I think the best one out there is the official ETS one. Since they put it out, they cannot misdirect you or give you wrong information. If they do, they would incriminate themselves and make their test invalid. What you can do is try to get ETS sample tests from years back. In this way, you will have several years worth of books. This is important, because the best way to practice for any test is by actually doing a lot of tests. Practicing tests is the key to getting a better score. Also by doing practice tests, you will quickly begin to see patterns of strengths and weaknesses.
It doesn't matter which book you "buy" if you don't use it and follow the instructions inside the book. The ETS books are the best books because they reflect the actual content on past exams. If you are in need of more practice than that book can provide, then I would suggest you buy one of the other books to practice with.
Having passed two content-area PRAXIS tests with flying colors and having purchased the ETS book for both, I agree that you should use the book, but I also think that relying exclusively on the book would be a mistake. The ETS book is useful because it allows you to practice that fine discrimination and close reading you need in a standardized test, but it provides little in the way of materials to study content, which you have no doubt already noticed. Since I have an excellent grounding in literature and composition, I did not study content at all for the English test. But before I took the social studies exam, I read extensively in each area covered, made notes in the margins of my books, and acted as though I were preparing to take a final in all the subjects. I would suggest the same for your test. If you do not have textbooks on the covered issues, acquire them used at your local university bookstore or an on-line source. The chances are good that the cost of this will be less than having to take the test repeatedly, and certainly the mental cost will be less if you are prepared and pass. ESL is the wave of the future, and a great certification to have.
I would use the official ETS book. I noticed that they now have an ebook. I think that may be better because you can get it online immediately. Sice the minimum passing score is 530, studying the best test questions and content is critical. The categories of the ESL praxis test are:
30 questions on linguistic theory
36 questions on assessment techniques and cultural issues
18 questions on professional issues
The test isn't so tough. (I completed a masters degree in TESOL.) After you teach for awhile, you can study online for a masters degree. I know a teacher who is teaching ELL at an elementary school and is working toward her masters.
I also would use the official ETS book. For the PRAXIS TEST, I found it to be extremely helpful! I think anyone reading through these posts who is getting prepared to take the PRAXIS, buying the book is so worth the investment. :)
I used to work for several testing agencies. I even helped put some of the questions together for testing. Even though I have not done this in years, I will give the secret to success. Each test is based on basic knowledge. This basic knowledge is taught in GED courses. Therefore, if you want to do well on any practical test like the: Praxis, GMAT, MCAT, LSAT, etc. then it would be to your benefit to purchase or borrow a book especially written for GED students.
I cannot go into more detail then that, but if you get one of these books (GED) then you will be fine.
Focus on the issues of maintaining the integrity of a student's first language culture.
It has been my experience that which ever Praxis test you are taking, study the offical ETS and ask anyone you know that has taken the test already themselves. If you like working on the computer, checkout the ebook version. The key to any Praxis is reviewing the material until you know it, not just trying to memorize it for the test. Good luck!