South Vietnam was a shitshow even by the low standards of Cold War shitshows. First it was ruled by a fundamentalist Catholic dictator in a Buddhist-majority country - you can guess how that turned out - and then after that dictator was couped and executed, a series of juntas whose leaders were not all that militarily competent, and who only held show elections crudely imitating multiparty democracy.

Effectively, the only popular support South Vietnam had sprung from suspicion that the Communist North might end up doing a little bit of purging should they win (a suspicion that was not wholly unfounded, unfortunately), but that fear only offered lukewarm support to the corrupt and authoritarian South Vietnam government, which did plenty of political repression of its own.

Effectively, there were no 'good guys' - arguably there never are, but nothing to the tune of 'Allies vs. Axis'. Of the two polities, North Vietnam had much more popular support, and was about as repressive as the South, at least after Ho Chi Minh was sidelined by hardliners in the mid-60s.

Vietnam is doing alright now. They had market-oriented reforms in the late 80s or 90s, and now they're one of the most pro-US and pro-free market countries in Asia. I'm given to understand they still struggle with corruption, but what developing country doesn't? Unfortunately, they remain a single-party state and fairly politically repressive. Ironically, these free market pro-capitalist reforms have all taken place under the single-party domination of... the Communist Party of Vietnam, the same one which ruled North Vietnam and overthrew South Vietnam.