The Americans have a lot more aviation experience than anyone else and in my opinion have correctly identified flying as a practical pursuit. Pilots fly planes they do not design them. The acid test of my opinion is quite simple. Ask any pilot with a JAA ATPL to sit the exams again and he will tell you that he would have no chance of passing them unless he embarked on a rigorous course of study again. Ask the same of An FAA ATP and you will find that he wouldn't be opposed to having a go at the ATP exam on spec. Why is this? Some would suggest that he US exams are a joke, not so.
The reason is that the US exams ask relevant questions with straightforward answers and anybody currently flying should be familiar with the content of the test. The European model on the other hand sets a barrier which must be overcome and once passed forgotten about. This really begs the question "if once I have passed these things I can forget them, then why did I have to pass them in the first place. Are the European Exams needed to ensure that pilots are safe? No, if they were then how come the 700,000 or so US pilots (who never did them)have as good if not a better safety record?