As one who was there. Our military won every single engagement they had. The over-hyped Tet Offensive was a massive loss for the VC and Northern Regulars.
The vast majority of South Vietnamese wanted us there and did not want the communist north to take over.
It was the media who hyped the anti-war movement and politicians in Washington who screwed up everything and lost the peace.
However, what is interesting - and doesn't get reported - is the resurgence of the free market, not only in the south, but all over the country. They welcome foreign investment and are actively touting tourism.