I've taken quite a few paid courses on Inflearn, and in every aspect, Lee Jeong-hwan's courses are the best. That's why I've taken all of Lee Jeong-hwan's courses. This React SNS course is great too. Lee Jeong-hwan's courses... 1. You can feel the preparation that went into the course while watching. => When you watch videos from other instructors, almost none of them prepare scripts. Most seem to only prepare content at the title level. As a result, when you watch their videos, they stumble, repeat what they've already said... Examples turn out differently from the results... In some cases, they swallow their saliva so much that it was disgusting, so I didn't continue watching afterward. However, with Lee Jeong-hwan's courses, you can feel that scripts are thoroughly prepared before filming. So there's no redundancy, and the progression is smooth. It's very satisfying, and it really feels worth paying for. 2. The course environment is well prepared. => Unlike videos from other instructors, the audio is consistent from start to finish. When you watch Lee Jeong-hwan's courses, he films almost without moving. This seems to be because moving prevents the voice from being recorded at an even pitch. 3. The course content quality is excellent. => When you watch videos from other instructors, most just type on PPT and show it. It doesn't feel very thoughtful. From the perspective of paying to watch, it sometimes feels like a waste of money. Lee Jeong-hwan's courses don't have screens shown through PPT. Everything is explained with animated screens. This allows for faster understanding. However, watching Lee Jeong-hwan's courses... there's a problem. When I watch preview videos of other instructors' paid content, the quality doesn't satisfy me, so I'm reluctant to purchase... Other instructors should watch Lee Jeong-hwan's courses and benchmark them. Inflearn should also benchmark Lee Jeong-hwan's courses, set them as the standard, and request instructors who want to operate paid courses to follow suit. Isn't it natural that better quality should be provided for paid content? So... I only call Lee Jeong-hwan's courses "courses." I just call other instructors' content "videos"... they're insufficient to be called courses.