I listened to everything from crawling to data storage. I'm listening to it with my company's money, but if I listen to all of the machine learning lectures and other lectures are updated, I'd like to listen to them even if it costs my own money! The overall lecture structure is good, and it's good to understand and move on while practicing in the middle, but when I look back at the lecture materials when I apply them to my work, I remember the parts I didn't understand! Fighting everyone :-)