When I was in grad school at UCF, they required all engineering degree candidates to take the EI exam. So, when I was wrapping up my MSEE I signed up for a test session. It wasn't required that I pass it, just that I take it, so I only did a small amount of prep and carried in two or three reference books.
Holy cow - people at the exam were wheeling in hand trucks full of textbooks and notebooks! How could you possibly use that stuff? On the morning multiple choice section, you only have an average of 2 minutes per question. Some take several minutes, so on the others you'd better be able to figure them out without digging through textbooks.
I made a solid passing score, but it seemed to me that the exam was more an exercise in test taking than demonstrating engineering knowledge. On many of the questions, only two or three choices would have the correct units, and one of those would have a numerical value that was two orders of magnitude wrong. If you could get the units and SWAG a ballpark answer, you had half the test already licked.
I never took the PE exam, though. In my field, it's not just that it's not required, it's downright irrelevant. And it is nearly impossible for me to even qualify for it, due to the requirement to be endorsed by several PEs who can attest to my qualifications. Heck, I only know two PEs at our place, and they've worked for me, not the other way around.
IMHO, the engineering licensing system in the US is a joke. 70 to 80 percent of practicing engineers are unlicensed, and have no requirement for it. Licensing is done by the states, and the states have no authority to regulate interstate commerce (i.e., most products) nor to regulate fields already regulated by the feds (communications, aviation, energy, etc.) nor to regulate direct activities of the feds (defense, space, etc.).
This is why you need a license to design a drainage culvert but not to design a nuclear cruise missile or an airliner.
The NSPE is largely out of touch with most of the profession, having only a small percentage of PEs as members. Yet they are responsible for state licensing exams. Hence the exams do not address the activities of 3/4 of US engineers.
Sorry, ranting....