Some Udemy courses are pretty good and are taught by practicioners, while Coursera is much closer to what you get in University.
Coursera -> Helped me to graduate
Udemy -> Helped me to get useful skills quicker and make money
Coursera -> Helped me to graduate
Udemy -> Helped me to get useful skills quicker and make money
Generally, looking at the number of students enrolled and the rating of a course gives a good idea on quality.