I've taken many paid courses with Coursera. Many have been outstanding.
However, I recently took the Technion Specialization for Creativity and Innovation. One of the main requirements and method of learning for that specialization is interaction in the discussion groups.
I had been locked out of the discussion forums due to a Coursera programming error, but was not made aware that I had been posting into thin air and that I did not see other posts until the last assignment before the Capstone Project.
In that assignment, we were to read all the responses to two discussion group questions and write what we saw as the general themes in those two discussions. Each student was to link at least five responses made by others in each discussion.
All I saw were my own posts. I waited until a half hour before the post deadline, and stated that nobody answered the questions except for me.
After I posted, I received links to grade others! The others had provided links. There seemed to be hundreds of posts, none of which I could access from my account.
I contacted Coursera, and they found that my account had been set up as isolated from the rest of the course. They called it "bizarre". They said that I shouldn't worry; I could still take the capstone even though I had not taken the courses as designed.
Even though I originally could have taken the courses for free, I had paid so that I could learn the material all the way through the capstone, which I obviously did not do. In contrast, others who paid for the course did get what they had paid for.
I told Coursera that I was not prepared for the capstone and they should cancel my certificates which were not earned as stated in the course ("and participate in discussion forum posting your opinion and commenting those of other participants" every week) and refund my money so I could start another specialization instead. I had wasted fifteen weeks of my time, and certainly did not get the value of a paid course over a free course.
They dropped the conversation then and there, ignoring all of my emails. My third course remains incomplete (I guess nobody marked my final assignment), they did not provide services as agreed, and they seem to have no mechanism for dealing with situations where they do not meet their obligations.
Besides this Technion specialization, I had taken other courses and another specialization, some concurrently with the Technion Specialization. I was very satisfied with those others, and had become a booster for Coursera. I had gotten friends and family to sign up with Coursera.
I personally have spent about US$900.00 with Coursera, but their lack of honor means I plan to never take another paid course with them. Meanwhile, I have since sought other remedies to get my money back for the Technion courses.
I recommend Coursera for free courses, but recommend you don't pay them anything. If you ever have a problem after payments and deadlines, you will be on your own.