I've been twice now. The first time in the late 80's when I did a week long tour of Saigon and the south (it took months to organise, and cost a fortune). That trip made such an impression on me, I never wanted to return, and witness the place as having changed.
I did however return in 1995, and did a much longer trip (in combination with Laos). I was relieved to see that even down town Saigon had not changed a great deal. Well the people hadn't, although most of the Amerasian children had gone (to the US) by then. There were some new hotels, and the place was sprucer. Oh and the 'Museum of American War Crimes' had rebranded itself, the 'Museum of the American war' or some such, lol.
Anyway, I digress. But Vietnam is a pretty life changing place to visit. I hope the country has not changed too much since then. It is incredibly enchanting, and beautiful. The people are by and large fantastic, the food is amazing.
Highlights from my last trip were taking a taxi to drive us from Da Nang to Hue. We had time to stop and enjoy and photograph the views, and some of the views on that coast road are just jaw-dropping. The palace in the centre of Hue (go to a few of the best ones in Hue, there are so many it is a bit like Kyoto, Japan, easy to get 'templed out').