These countries and their situations were alike in several ways. For example, North Korea had ideal principles like one dictator and anyone/everyone must obey and be orderly, this is seen similarly in North Vietnam.
Both Korea and Vietnam divided into 2 after WW2 ended. As a result of the Korean and Vietnam wars, several thousands of people were killed in both countries. On the other hand, the Vietnam war lasted a lot longer, so it would be suspected, that there would be quite a few casulaties.
America sent troops to both of these countries to contain communism, and in both countries, communisn prevailed. Both countries had been under control of foreign powers up until mid 1940's.
The US sent troops into both of these wars for different reasons. For the Korean war, the US really needed and wanted to stop the spread of communism because that influence in Korea could've started the domino effect. The US wouldn't have been able to stop communism if North Korea did take over South Korea and made it a communist dominant country. Today, N. and S. Korea are still divided, however, Vietnam is no longer divided and under communist rule.
The US sent troops into the Vietnam war, not so much to stand against communism (although that also was a large component) but by the end of the war, they had removed all of their troops and instead were just protecting the border. The US groups with the more evolved equipment stayed a little longer, and were forced to be more careful while watching for the enemy.
The Vietnam and Korean wars were also different because while the Korean war was only 3 years, the Vietnam war stretched on for roughly 10 years, give or take a few years. The US was able to protect South Korea from communism, but not South Vietnam. Unlike Korea, Vietnam was a guerrilla conflict. This means that the North Koreans fought for themselves, while the North Vietnamese needed the Viet cong, under the rule of Diem to help them.
TV forever changed the way people looked at war. The people in the US were being protected from what was really happening in Vietnam, only to realize that this war was turning our people into monsters. When it came out on live telivision, videos of American men burning down villages to the ground, people immediately retaliated and started uprisings against war, especailly the Vietnam war.