At my university in Germany the trade-off is at approx. 50 students in a course when written becomes much more efficient. I can take max around 12 oral exams a

At my university in Germany the trade-off is at approx. 50 students in a course when written becomes much more efficient. I can take max around 12 oral exams a day mostly it is rather 8. The point is that the written exam is largely outsourced to PhD students here. The professor only looks at the model solution before and the grade distribution afterwards in extreme cases. Also you can parallelize the grading so that even for 300 students the grading is done in a week. Typically the professor spends half a day otherwise it would be 2 month... I only do oral exams for my course and I am very happy how well it works. I normally ask students to grade themselves afterwards and I am typically spot on (I have written down the grade before).