The short version
Hoang Quoc Viet is a north western arterial district linking Cau Giay with the lake side. Universities, offices, towers and older streets make it useful for a professional or student who wants access without moving into a compound. The main road is the obvious compromise.
The side streets are where the area becomes more liveable. They retain small businesses and a closer street scale, while the arterial carries the traffic and commercial frontage. Check the crossing from home to shops, and visit the bedroom during the day before assuming that a rear facing flat is quiet.
Hoang Quoc Viet is a good bridge address when your life spans several western districts. I would choose it for access and services, not for leafy calm.