My biggest problem with the official study guide for TOGAF that it only appears to be available in PDF format. I like to scribble in a book as a study. For only $20, this book comes printed. Kevin Lindy's book also has the advantages of being shorter and having more practice questions. Good news all around.
Some of the questions in Kevin's book are harder than the real exam questions. Especially "which 5 of the following 8 are true" type questions. But they were good for reinforcing knowledge and looking for keywords in the answers.
I found a couple of questions with suspect errors so I had to take off a star or two. But it was still worth it. I found it significantly easier to learn from Kevin's book than then official study guide. It was a great investment of $20.