ProbablyJustGas, I went to school in an 'exam is everything' system (Ireland) that is now starting to incoroprate coursework into the final grade, a godsend for students who are laid low by hay fever at exam time (start of summer) but also for students who collapse when faced with exams. My older DCs went through high school in the US as you seem to have. They worked far harder and far more consistently than I did, and for four years in a row instead of four months before the two major exams I took.
For all of its faults, the Irish system offers a solid education that is availed of by approximately 80% of teenagers.
For those of you suspicious of plagiarism and other issues -- the DCs also did AP exams, administered nationally, where the final result depended on exam performance, and SAT and ACT exams, also administered nationally, which can be repeated, but basically they measure your performance in that one exam and pay no attention to your coursework. They are standardised exams. Students at the top of the class in every subject according to their school results (grade point average) tended to do really well in the APs, the ACT and SAT, and often in the National Merit competition too.
Incidentally, the system there also allows for an element of grading on the curve, both at the individual teacher's discretion in the classroom and when the National Merit Finalist scholarships are handed out, based on results of the PSAT, taken in junior year (second last year). National Merit was actually a little unfair because grades were compared to others within your state to determine the top half of one percent who were eligible for the scholarship. A score that would get you into the top echelon in Arkansas (for instance) would leave you among the also rans in other places.
All of the questions associated with standardisation, etc., have been pretty comprehensively ironed out in the US.