I just got back from a trip in Vietnam, I made my way from North to South in just three weeks so my sample size is pretty small, but I pretty much agree with you although the bros/backpackers are definitely not limited to Ho Chi Minh City. Hanoi was my favorite place, it's a crazy yet charming city where you can't escape the green of the jungle - I've never experienced anything else like it. I will definitely go back, it's one of my favorite places on the planet. The only caveat for me is in fact the smell of pollution, as mentioned in the article.