I signed up for both of these courses, so will give feedback to those who are interested. (There are MANY courses on Coursera.org alone... and others on Futurelearn.com, but I will speak only to these two specifically).
First, I had no real expectations going in, but was actually incredibly disappointed with the "Songwriting" course. I had assumed some music theory (even any music theory) would be involved, but it came across as "glorified poetry" to me. As I have taught college English, I was annoyed that I was sitting through long-winded poetry lectures that I could have taught in 1/10th the time. Ironically, someone (who apparently camps out in each class' forums) dropped the entire course note set in one post, and another with "links from past classes" during week 2. That was enough for me to download them and un-enroll. In hindsight, I wish I had known the true content of this class before it started. Perhaps someone who participated in this one fully can chime in with their impression.
Introduction to Music Production on the other hand, is loaded with nice information. The lectures are succinct (and can be downloaded), and the forums dropped a lot of good information as well. The class can be audited for certain, and a lot of learning can be had even not taking this "for grade." The assignments were many people's complaints, but I took the perspective of challenging myself to also learn video, since many posted these assignments on YouTube. So from that perspective, I learned a lot more than simply the "content" of the course. Introduction to Music Production also has a lot of applicable content to posts that appear in this forum. Participation in the forums (there) is highly advised if taken, as a lot of useful information is also passed on in those (upwards to the same level as the lecture content in my opinion).