Hi VS,
I used the book whilst going through recruiting this year and must say it was an invaluable resource. There are areas in which the book is inaccurate (only this such as aircraft in service, pay rates etc - anything that has changed since it was published.) The Defence Jobs website really doesn't push the study and prep as much as it should (particularly for a pilot - it is a very competitive position). I ended up committing most of the info in the Wings book to memory; the defence interviewer said I was one of the best applicants she had ever interviewed. That got me onto flight screening shortly after. Study just as much for your OSB and you'll be leaving Tamworth with a high recommendation. AS long as you double check anything that may be outdated in the book you'll find it to be very useful.
Cheers,
Steve