My experience as a past student and ta has been that courses with TAs have less dependence on the book, and problem sets are more likely written by the professo

My experience as a past student and ta has been that courses with TAs have less dependence on the book, and problem sets are more likely written by the professor. A TA saves a prof vastly more work than using a book with canned problems, and the cost of writing problems is amortized in large classes. Smaller classes without TAs (which should ostensibly have better instruction) tend to fall into the textbook trap more often.