I don't know if it's just me, but a lot of people have trouble with the TFE portion of the PAT. For TFE, crack pat is not exactly the best. They throw difficult problems at you without easing you in. If you're having trouble with any of the other types of problems, then it's definitely worth the money, but IMO TFE is the most difficult portion of the PAT, and crack pat does poorly to initiate the TFE-challenged.