I would describe Gyeongju as the Korean Equivalent of Kyoto or Nara, only not as well preserved. There are fewer historic structures and monuments standing compared to what you will find in Kyoto.
I stayed in Gyeongju for several days where I was able to spend time exploring this site as well as the nearby Seokguram Grotto and Bulguksa Temple.
I thought that Gyeongju was the best site I visited in South Korea.