Best answer by hamster
So, if you are asking how 'intense' the assignments are because you are the type of person get anxious/stressed by exams my advice would be to just relax; Remember that failure is part of learning and that coursera provides a "safe way" to fail.
Lastly, I'd say that quizzes and assignments tend to be fairly forgiving on coursera. For example most quizzes you get 3 tries to pass. What if you fail? Well, your "punishment" is to wait 8 hours before you get to try it again.
In short: If you want to learn something just give it a go! You have basically nothing to lose and a whole lot to gain.