This is hands down the best MOOC I've taken so far on any subject. Both instructor's lectures excel in both choice and presentation of content, and the writing assignments force students to think about and understand the material to some degree of completion.
Suggestions: There should be a non-trivial graded writing assignment every week. In the whole MOOC format, peer-graded writing assignments are the only instrument developed so far serving as a meaningful assessment device while forcing students to think about the material in a more than casual manner. The multiple choice quizzes are easily passed by listening to lectures and the material is quickly forgotten afterwards. Students submitting late may also be given the option to transfer their work so far to the next offering of the class.