I found the Q&A book and PPL confuser very useful because, never having sat CAA exams before, I had no idea what to expect, what sort of style etc. that the questions would be written in.
Although I studied my little socks off, I did get into a bit of a tizzy before I sat my forst one as I didn't know what to expect and it is to this end that the "quiz" type books are useful.
Cheers
Whirlygig