I have taken more than 85% of the course. (I have taken all of the courses except for the WebSocket~CLI part.) Advantages 1. It is detailed. Even though it is the same concept, Zerocho's course covers it much more in depth. 2. You can see the textbook. At the beginning of the course, he says that you don't need to buy the textbook, but from my experience, I definitely recommend buying it. 3. You can learn about other parts (testing, deployment using AWS, etc.) in addition to the Twitter backend. 4. The Q&A board is very fast. They answer in less than a day. Disadvantages 1. There are some parts where the explanation is not detailed. This is especially true for the Sequelize part (follow, following, like function). It was difficult overall, so I didn't even know what to ask. In my case, I studied by purchasing the course textbook and taking the free database course of Saengwhal Coding, but I'm not sure if I understood it properly. 2. The front-end is implemented with vanilla JS and axios requests, so it is a bit lacking for a portfolio. For those who need a portfolio like me, the Nodebird Clone Coding lecture seems better than this lecture. Overall: Although there are some shortcomings, I think there is no other Node lecture as good as this in Korea. It was of better quality than the lectures that YouTubers put out for 200,000 won.