I believe they're ten weeks long.

Whether they will be easy to follow or not will probably depend on how much free time you have now. I work fifty hours a week and socialise often and have found it difficult to keep up with all three courses currently running. I imagine for someone in my position two would be the sweet spot.

I started taking the Machine Learning class while going to school full time and I had to drop out. It was just too much. I also work full time and have a toddler, however. If I was single I think I could handle it.

I've gotten behind in that class as well, but I plan on downloading all of the videos soon so that I can at least go through them without doing the quizzes/exercises next year.