In regards to hospitals in SE Asia, I've worked in the local and international hospitals in REP and KCH and would not hesitate to use them as a patient myself. I've never been to a US hospital so can't really compare there.

In regards to dengue and malaria, yes the risk is there. Same as there's a risk of Lyme disease or West nile in USA, or ross river or murray valley in Australia. Arboviruses aren't restricted to a couple countries!

Agree with others that Hue is nothing special, spend more time in Halong Bay instead