Documentation is extremely important.
Then don't buy it until the documentation is up to spec! Who do you think you're kidding here? You're just as eager to get new toys as everyone else. Besides, only girls read the documentation. New question: Imagine that you haven't yet purchased Blitz Max, how much would you pay for it now knowing the lack of documentation that it comes with?
People keep saying that, yet they have yet to provide an example of a comparative product that is nearly as well documented as BlitzMAX. I can only attribute this expectancy for documentation to inexperience. I think you'll find that's the other way round esp. when compared to what will actually help you complete a game ;-)
The only thing that will help you finish a game is discipline and determination.