My brother and I traveled to South Korea a couple of years ago. It was great. We stayed there for six days and then traveled back just in time before a hurricane hit Japan, which was our layover.
The people of Korea are very welcoming, albeit a bit reserved and protective of their culture. The United States has had a presence there since after World War II, so they are very familiar with all things having to do with America. As a result, you kind of feel at home even in such a far away place.