I have taught both JAA and FAA syllabus, both have their merits. The FAA system works extremely well if there is plenty of flying available to build hours and experience (ie regionals) prior to moving to the larger jets and obtaining ATPL. In the States there is a lot of commuter flying and it works well.
The JAA system works well for pilots joining airlines with low hours as it tries to replace the lack of experience with enhanced knowledge. This is often the case in Europe where the means to build hours are more limited.
Once established as a type rated pilot with experience it is as previously mentioned down to the individual, with good and bad from both systems.