KAIST is one of the best universities in Korea with many opportunities and the best students. There you will face high competitiveness that is good and bad at the same time, it helps you grow and become more diligent however it might affect your personal life and self-esteem. Generally, it is hard to keep a high GPA, and because of relative grading, you gonna study a lot, probably even sacrificing your free time and personal life.
However, if you are not afraid of that, then go for it. University has very good research opportunities and facilities, and a full scholarship covering your tuition. Certainly, you gonna face a language barrier outside of the campus so it’s better to know basic Korean at least.
I studied aerospace and electrical engineering, I am satisfied with the knowledge I received.