Maria Pascua completed this course, spending 3 hours a week on it and found the course difficulty to be medium.
This course is fine only as a warm-up before a more serious and better organised one. You will be introduced to sounds, tones, numbers and other basics. I would not pay for it or for any of the three specialization courses as it is not very student-friendly (old videos, mistakes in audioscripts, poor editing...) and also the quizzes (practice and final ones) are full of errors. The organisers do not monitor the forums or the technical mistakes alerts so it gets more and more frustrating as weeks go on. As I have mentioned before, I recommend you take on the few useful features from it and forget about test scores or interactivity. Afterwards look out for better courses on Class Central or Coursera (Read student reviews!).