The short version
Van Dien is a southern rail and market town at the edge of the built up city. It offers local commerce and a practical connection to surrounding districts, but its infrastructure led setting is not a softened version of central Hanoi.
The market and railway give the town an identity, while housing and industrial edges make the wider area feel transitional. Inspect noise, road crossings and the route from home to the station or bus. A resident who works nearby may find it straightforward. A central commuter should test the whole journey before committing.
I would choose Van Dien for a local routine and clear value, not for polished urban life.