I used several sources for my PMP Review. The LeRoy Ward practice test listed here, Rita Mulcahy's PMP Exam prep and Headfirst PMP are the most noteworthy examples. The two other books are good for getting a basic understanding of the inputs and outputs of the project management process. To get questions that go deeper, and are more similar to the real PMP test, you have to get this book.
I reviewed these practice tests the week before my PMP test and was shocked at some of the answers to the questions. There were details within the multiple choice that i hadn't noticed while reading the PMBOK or the other review material. A couple times i said "No, this can't be right", looked up the answer in the PMBOK and sure enough got proved wrong.
When i took the real test the questions were on par or easier than those in this review. I was pleased to have studied down to the correct level of detail and was fortunate that my friends at work set me up with this title.
PS I passed!