PPSC is painful!
I've done 5 subjects through their books and it was hard times.
There books don't teach you exactly what you need to know to pass and there's sooo much info in them, half of which you don't need to know.
There questionaire system wasn't the best as they would just reply back with the questions you got wrong, they didn't actually give you ideas to improve yourself.
You need to be pretty deticated to pass through the PPSC way, alot of study required.
I just sat Adv Aero yesterday after doing a course through
www.waypoints.co.nz, felt I did well and instead of studying for a month prior to the exam I only sat a 4 day course.
You can learn so much more with a person actually infront of you teaching.