B747 and Mr. Hat,
I know people that have made it through (both as cadets and d/e) without anything more than a couple of books to use as practice.. I also know people who have done the preparation courses and thought that they meant a free ticket, but ended up being knocked out at stage 2 or 3.
Someone gave me a great piece of advice when I started preparing my application - and that was that I might be better off spending all that money (that I would have been spending on the prep courses) on a nice new suit and some study books - and even maybe take some time off work to hammer out some solid study.
But I do agree with cudza when he says that it depends on how you feel about the exams/interviews. From what I hear, those courses are fantastic in terms of interview preparation especially... Not too sure about how they go for exam/psych test practice.
Good luck with it.
mins
