Yeah, it really is personal preference, but I would say that if you've been out of school for a while, I wouldn't take a CAT first. I would start with the PR book to get an understanding of the test. Read through the strategies and do the practice questions in the book.
If you're feeling fairly comfortable with your initial practice (including review of the fundamentals with math especially), then try one of the CATs. If you're feeling rusty, then I would start working through questions in the OG. Do some in each section, and after a week or two take a CAT.
I think many of the people who are successful do practice questions in the OG on weekdays, working through one question type at a time and reviewing errors carefully, then taking a full, timed practice test each weekend.