Beijing or Seoul?

Hi all, i’m a student in the United States looking to study abroad next year. As of right now, im debating on Tsinghua University in Beijing or Yonsei University in Seoul. I was wondering if anyone had any similarities/differences or pros/cons on the two, or an opinion on which of the cities you think is better(cost of living, stuff to see, friendliness, etc.). Any advice is greatly appreciated.