I've been in HCMC for almost a year. District 2 is getting a bit rough. Two of our guys had their backpacks grabbed while on their scooters. District 1 is fine, just grab a cab, cheap and all around.
What I can't get used to is the filth and lack of sanitation. Local restaurants with no soap and half with no running water to wash after using the toilet. Rats running, often walking, thru restaurant's eating areas. Local men and women urinating on the roadside during the middle of the day. I was sitting in a park near the back packer area, a local walks up to a tree and relieves himself in broad daylight! 30 meters behind me were public toilets.
Safe but a 5th world city. Da Nang is much nicer but there are no bases there.