How would you rate the prerequisites of each course and level of material covered? I've never taken Andrew Ng's ML class, but the impression I get online is that it's great but it's always hard to tell from these positive reviews if the course is just an introductory exploration or something more in-depth.

In my experience, there’s a vast difference between “education” aimed at the individual and what is delivered in accredited academic courses. The commercial aspect / tailoring to get people to buy and stick with it / no doubt is a factor.

229 is a 2xx class for advanced undergraduates and beginning graduate students. It's a first course in machine learning with no AI prereqs.

What grad class did you take?

https://www.cs.columbia.edu/education/ms/machinelearning/